Short answer: about $750 - $800.
Longer answer:
Serial # A6300XX is circa 1980.
You mention "foam" in your description of the box which make me wonder about the originality of the box(?).
The original box for that vintage (1980) should be in a dark blue 2 piece cardboard box with white/silver lettering and metal reinforcements along the corners of the box in a matching dark blue color. There will be an oblique line pattern in the same white/silver around the edges of the top portion of the box. The upper left corner of the top portion of the box should have the S&W emblem in the upper corner and the lower right corner of the box should have "of Bangor Punta" or "A Bangor Punta Company" between "Smith & Wesson" and "Springfield Mass." There should be a label on one end of the box with identifying information for the firearm original to the box. As best I recall and determine there was no "foam" in these boxes. The interior of a box for a Model 41 circa 1980 would have cardboard cut-outs that fit the profile of the model 41.
The SCSW (Standard Catalog of Smith & Wesson) 4th edition, now about a year old, suggests the following values:
ANIB (as new in box) $1300
Excellent condition $900
Very Good condition $750
You describe a gun in (most likely) excellent condition but I doubt the box is original (?).
A quick look at Gun Broker for successfully closed auctions (i.e. the gun actually sold) suggests the above values are fairly consistent with Gun Broker sales.
It's my opinion the above values, the SCSW and Gun Broker, are closer to retail values. You might deduct 10-15% for a private sale (?).