Ok, A MINT condition gun like that would bring around $1600 according to the RENE price guide. A 95% gun, if NRA graded properly, would likely be in the $1200 or so range. Then the box,, can add some to that. If the shipper is included,,, then the prices goes up even further.
Johnnu2,, yes,, as noted above,, there were a number of the 7-1/2" guns actually shipped with a 6-1/2" bbl. It was a mistake as Terry said.
Often it's called a S-47,, OR,, a S47-6-1/2"
A factory letter is mandatory to secure the higher pricing.