Nice revolver, you didn't get hurt a bit! I would have payed that in a minute.
They are not N-Frame stocks, just from a different gun of a few years later vintage. At this period, and into the 1970s, Stocks were hand fit to the specific frame they were fit to, hence the reason the SN was stamped on the inside of the right stock. If they were N-Frame stocks they would over-hang a lot, about 1/8", at the rear, not at the front. Contrary to what some believe the only difference in shape between N and K stocks is from the level of the screw hole up to the "knuckle" of the frame. The knuckle is the corner of the frame behind the hammer. The over-hang tapers from top to bottom, with the greatest over-hang being right at the knuckle.
A supposedly knowledgible LGS had one in almost identical condition they were asking $800 for! They had it for over 2 years too. If it had been $500 I would have bought it, but they wouldn't budge! But the stocks were at least correct vintage, probably numbered correctly too.