An original sales catalog (PDF).

According to Kessler Music, there were two models made: 72HB-STD (standard), of which there were 300 produced for the USA, and 72HB-LTD (limited, with darker lacquer), of which there were 70 produced for the USA. (This flyer from Selmer shows the difference in lacquer colors nicely.)

These are just reworked Reference 54 altos with some extras:

* Custom "Bird" engraving on body and neck
* The neck has a red background for the "S," rather than the traditional blue background
* A specific "Bird" ligature
* A "Bird" case, which is a form-fitting hard case with an imitation leather exterior
* A silk embroidered pouch for the sax's accessories
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I've seen these selling for $5200 to $5700, recently. Note that I didn't say "sold for."