If it has a full-lug barrel it would be a model 16-4, like the top two guns pictured. All earlier versions of the model 16 and it's predecessor, the K-32, had non-lug barrels like the bottom gun. While the earlier guns are scarce (only 3630 produced 1948-1974) and therefore command a much higher price, the 16-4 also had a fairly limited run (8800 produced 1989-1992). The 16-4 came in 4", 6", and 8-3/8" barrel lengths, with the 6" being the most common.
From what I've seen, a 16-4 in excellent or better condition with box, papers and factory combat grips will usually sell in the $800-1000 range, occasionally more. The 4" barrel versions seem to bring the higher prices. The 16-4's came from the factory with the wood combat grips shown in the picture, and they are valued at well over $100 by themselves.
IMO if your gun is in very good condition with the original grips, no box or papers, it might be a $700 or so gun.