As a result of some of the replies here, I went and dug out (and you have no idea how literally apt this verb is) an old marked A&S jacket (Class of '78!) from my closet. The comparison of the lapel buttonholes is interesting. Here's the A&S:
And now here's a shot of the underside of the lapel on the first jacket:
Both buttonholes are 1.25" long. Both show a hint of a curve; the A&S perhaps a bit more so. Both begin on the axis extending down from the lapel notch parallel to the lapel's edge. The A&S buttonhole ends 3/8" from the edge of the lapel, while the buttonhole on the unmarked jacket ends 1/4" from that spot--this is, of course, the big difference. An unusual feature on the unmarked jacket is the length of the buttonhole guard, which at nearly 1.5" in length is longer than the buttonhole itself and extends to the very edge of the underside of the lapel. The guard on the A&S jacket is properly discrete, measuring in at an unimpeachable 1".
So, have these lapels been altered? I don't know. Would someone really go to the trouble to shave off perhaps 1/4"? Maybe. Interestingly, in keeping with my taste for the unrestrained, the lapel buttonhole was one of the first things I really liked about this jacket. I guess I like a bit of flash in the buttonhole--which this one supplies in spades. I'd be disappointed if it were a bit more discrete. I shudder to ask, but are there any rules about the size of the lapel buttonhole in relation to the width of the lapel?