Here is a unique find - an nice 5-digit Selmer Mark VI alto sax with an original factory high F# key, serial number 83539. It is in excellent shape physically and is a nice player too!
To answer your first question, yes, this horn has the medium bow, which makes intonation much better than the VI's with the longer bow. The factory high F# makes the sax pretty rare, as this was only a custom offer from Selmer, and not taken by many players at the time (who would want that extra key?!). Of course now, many players can't play without it!
This horn is in crazy good condition. It has just minor playing wear, and is in excellent shape physically. The original lacquer is 95% intact, and there are no dents or dings anywhere. There is a single resoldered joint on one foot of the low Eb keyguard, which was done so well it is almost impossible to spot. The original neck is in excellent shape, with just minor lacquer wear.
Sonically, the horn is a great player. It has the darker free blowing sound you expect from an early 5 digit VI, and responds evenly in all registers and at all volumes.