So after doing some digging around because i realized I couldn't find an American Standard that looked like this:
-I think it's a holton Collegiate possibly or stencil?
Otherwise i am too lazy to dig, but can spout off what i recall from last time i wasn't too lazy.
It shares the collar on the bell that old Holtons frequently have. But the bell does resemble a king bell in that there are no joints in it. And American Standard is one of the names that merged into King through Cleveland Instruments (failing to recall exact name) although American Standard was also used be used by Lehnert out of Philly. But i would be surprised to find they made a sousaphone.