People will definitely weigh in with their opinions, but to add a little empirical angle to this discussion I measured the vintage 1960s Deansgate jacket from the Harvard Crimson shop that I have posted in the thrift exchange. It's a beautiful grey herringbone Harris Tweed with all the details you mentioned plus:

- Lapped seams are 1/4"
- Pretty much all the seams are lapped including the back
- Regular flap pockets
- Hook vent is 9" deep
- Button-hole on the lapel is closed
- Cuffs are non-working with 2 buttons

The only detail that's missing is that this jacket has a removable throat latch.

 

Thank you dexconstruct for the quick reply and pics. So sleeves buttons are without closed button-holes, they are only applied on the cuff fabric and the cuff is all-round without any cut in it, right?

 

First, a sort of strategic thought: Of course, every jacket worn in the 50s/60s (even at Ivy League campuses) wasn't identical. There were even (shudder to think) people who wore two-button jackets with darts. To some extent, what I think you're trying to do is come up with something that's as recognizably 50s/60s/Ivy as possible. In choosing an option, the considerations that would favor a particular one would thus seem to be something like:
- that option was common in the time and place;
- that option distinguished that time from the other times, most notably the present (in other words, it was more common then than before and, particularly, since)
- that option distinguished that milieu from others (in other words, it was more common in the "Ivy League" setting at the time than in the broader world, particularly Cleveland)

Some of your details are beyond me, but a few to note:

- Patch and besom pockets were, I'm pretty sure, both fairly common. I suspect besome were more common, though that's just a guess. But given that patch pockets have since somewhat fallen into disfavor, I suppose patch pockets make it more identiable trad-era.

- The 50s/60s sack was really an OTR phenomenon. Pre-WWII, people (even students) would have gone in heavily for custom-tailored wear, but the rise of the 50s/60s look now called "trad" was essentially part of the whole post-WWII move toward ready-made, standard consumer goods (as much as that may sound vaguely counter-intuitive). So: no working buttons. Nobody in his right mind would have put working buttons on a jacket in the period in an attempt to fake a bespoke suit. Real bespoke suits of the period would have tended not to fit your trad mold.

- On the sleeve cuff detail, my impression, for what it's worth (not much, as others here are more studious observers of trad), is that you would have on overlapping vent detail under the buttons, just as is standard nowadays. With the possible, and unlikely, exception, of people whose arms are so short that the whole detail gets taken out in alterations. The buttons, to my mind, should just be attached without buttonhole-stitching around them. Unnecessary additional observation: flat (non-shanked) buttons can just be stitched down flat, without the shank-like sewing detail a real button would have. Shanked buttons go on blazers (always) and heavier/more country-ish tweeds (sometimes).

- I can't imagine anyone will notice whether the button hole is open (assuming you mean the one out there on the lapel?), at least not until you put something in it. Aren't they typically openable? In other words, it's just closed because the owner hasn't bothered to cut it open? To the extent the question really breaks down to whether you should put something in your button hole, that strikes as more an English or European thing, which kind of makes it non-trad. Also, it would be too busy to have something in your button hold along with your fake secret-society pin.*

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* Don't take that seriously, or wear a fake secret society pin.

 

Here's what the cuffs look like from the Deansgate jacket. Again, these are presented in the spirit of empiricism and with no judgement except that if you cut an identical jacket to this one you will have a beautiful jacket.

 

- Button-hole on the lapel is closed

I've noticed this wrt quite a few vintage traddy (Corbin, Deansgate, Canterbridge, Julliard, etc.) - why is the button hole closed? It doesn't LOOK as if it's supposed to opened, but I haven't asked a tailor.

 

My understanding is that the top buttonhole is a non-functional remnant from an earlier style of jacket that allowed you to button up the lapels. There would have been a corresponding button under there right lapel. In any case, I find that this buttonhole is often open on older jackets, when it was more common to wear a flower or boutonniere. Personally, I cut these open myself so that I can wear my pocket watch like the Rev. Dr. Peter Gomes.

 

The vintage sport coats that I have tend to have no button stitching at all on the lapel.