I have not seen a full Buescher-made Aristocrat or 400 Aristocrat bass, though. After the Selmer buyout, Selmer continued distributing some of the Buescher-made horns until about s/n 405xxx or 406xxx (1965). View the manufacturing date ranges on serial numbers for many of our legendary brands.
Post 400 'Top Hat and Cane' and Aristocrat 'Big B' Models One of the most interesting challenges is to define the last couple of models of and. There are definitely a bunch and they do not seem to accurately correlate with a specific serial number or model number chart. Making matters worse, serial number data is in 'chunks' after 1952: most serial number charts switch from a 'yearly' end serial number to a 'every five year' end serial number, or a variation thereof. Additionally, there seem to be a random number of 400 'Top Hat and Cane' and Aristocrat 'Big B' models still around after the introduction of newer models.
To complicate matters one touch further, there are at least two different 'numbers' associated with a Buescher: a catalog number, which is generally in the form of 'S80' or 'B7' (the 'S' or 'B' as a prefix appears to be random, but it may indicate a plating choice) and a model number, which is on the horn under the serial number -- which isn't included on all models. This is generally a number in the 1xx range, like 140, 141, 157, etc., although sometimes the model and catalog number is the same. Finally, there were bass and soprano models occasionally available. Mostly, these appear to be True Tone models with slightly more advanced keywork, but sometimes with new-style engraving and occasionally newer tooling. They were once again 'catalog listed' in approximately 1960. Main Models Available After the 'Top Hat and Cane' and 'Big B'.