I also recently acquired a Buescher Aristocrat tenor (for my son) which I have been trying to identify. It looks exactly like the one in the pictures linked above. The engraving is a block letter vertical "Buescher" and a smaller script "Aristocrat" above and at a right angle to that. The serial number is 111XXX with S-40 below the SN. From what I have been able to finde from searching the web, my best guess is that it was made by Buescher after they were bought by Selmer in 1963.
I would like to point out that according to the Selmer SN info at http://www.conn-selmer.com/content/resources/serialno.php#Selmer
the SN is in the range of Selmer's SNs for 1963 which is about the year that the previous owner purchased it (used). Is it possible that immediatly after Selmer acquired them that Buescher-made instruments used Selmer SNs for a while?
I would like to point out that according to the Selmer SN info at http://www.conn-selmer.com/content/resources/serialno.php#Selmer
the SN is in the range of Selmer's SNs for 1963 which is about the year that the previous owner purchased it (used). Is it possible that immediatly after Selmer acquired them that Buescher-made instruments used Selmer SNs for a while?