Supposedly, there were 100 to be produced in each gauge, but how many were actually built and sold is likely only known by a very few.
EDIT: Doing a little more snooping around, a letter from Jim Rikhoff of The NSFL confirms that there were indeed 100 20ga. NSFL guns produced and sold and that 100 would also be produced in 12 and 28ga. of this special edition . Scroll down to the four page letter in this thread:
https://parkerguns.org/forums/showth...ht=NSFL&page=5