Don't go calling your post selmer buyout Bueshcer "Bundies"
HA Bundy labeled horns were Aristocrat bodies with less "hip" keywork. So was elkhart built by Buescher horns.
After selmer buyout there's still one good batch of buescher - buescher horns. And I've always worked primarily with Bueschers and have measured more bodies and details than I should, so here's the breakup:
Aristocrats made out of prime production pieces: those horns will always have the rhomboid post and guard feet (flange). Top notch Buescher production on aristocrats, 400's, and mixed series (aristocrats with 400 bells and such experiments)
Aristocrat stencils: will have the true tone style flange for posts and will have the post selmer guard feet (flange). This goes for HA bundy, Elkhart, some WINDSOR stencil horns, well, that kind of horns.
during the early Selmer years, and up to mid 400xxx serial range, they're still using top notch details.
After mid 400xxx serial range, you have buescher bodies with stencil keywork up to 65xxxx on tenors and up to as high as 79xxxx on altos. This means that while having the truetone side trill looking keys (the aristocrat side trill key style were destined to Signets in this period) and the New Aristocrat LH pinky table with the no-rollered G# table that says BUESCHER or BUNDY, these horns are indeed pristine buescher bodies (the necks on this horns are True Tone necks in bore and shape, while the aristocrat necks are saved for signets occasionally and buescher 400 always)
So really your bundy I is a BUESCHER and not the other way around.
When you play a late 30's to '50's buescher you get why Selmer bought them out and destroyed them. They produced fast keywork, and a variety of flavors for intonation and tone (spread, thick and focused, etc) way before Selmer came up with the "celebrated" MK VI. (They must be celebrating now the vast amount of money they made with marketing hype)
I will make a point out of recording samples with my early, mid, late true tones, my New Aristocrats, My aristo I, my early Big B, my mid Big B, my 140 script aristo, my 400 THC and several so called bundy bueschers and post them. (I have all them breeds in altos, not on tenors) so you can take an educated or uneducated guess... the later aristocrats outplay my 140 and my later big B, and they're amazingly biting at my 400's ankles!
BOTTOMLINE: tenors up to mid 600xxx serial ranges and altos up to late 700xxx serial ranges are Buescher by all means and should not be taken lightly or as cheap student horns. The nickel plate may or may not appeal to you, and on the later edge of that ranges they may look cheaper than before, but up to about the '80's the selmer american company was paying the bills with overproduction stock from the golden years. even with round post flanges!
It's so sad learning that part of the reason why Selmer was allowed to do this is because you didn't stand up for your domestic companies and while having such fine horns made at the home of the braves you were always looking across the puddle for froggie saxophones!