Very nice 3 1/2" 27-2 you picked up there man! I know you will enjoy it. As for when it was made, most probably 1970-1971 if it is a 5 digit serial number. The Standard Catalog of S&W shows the N1-N99999 serial numbers being shipped in the 1969-1972 time frame. One other thing that makes me think it's an earlier gun is the difference in the placement of the S&W emblem on the sideplate and the cutout on the right side grip. On mine, the emblem is placed further to the right and a little higher, closer to the recoil shield and my right side stock doesn't have that cutout to clear it. Mine was shipped in the late 1973 to early 1974 time frame. Check the last pic I have attached showing the right side stock and emblem.

Last month I bought a nickel 27-2 3 1/2" myself, but came with a presentation case and the silver box too. And yes, I paid quite a bit more than you, but I really like the whole package of gun, silver box and presentation case.