Up close real stag will have a completely random nature to the surface, especially on when you look at it very closely. Under maginification you will see no machine or grind marks. Most bone jigging is very obvious, but some of Queen's new carved stag bone can fool you from a distance, but not up close. If it looks like someone used a dremel to make the surface appear like it does, then it's bone. Fake stag (plastic) will have the correct surface texture, but will be very obvious. The dark color on the surface will be a very thin layer (look where the scales change to white, like near the bolster). It will be a very obvious surface-only color. And the white part of the stag by the bolster will be very uniform. Most older real stag that you see at flea markets is not uniformly white where the surface has been ground off by the bolsters. Plastic will also feel like, well, plastic. Perhaps the best way is to look at some real stag. See if you can find some knives that you know are real stag (like Puma, Bulldog, Eye Brand, maybe Case) and get a feel for the range of feel and appearance. There are some brands, like the above-mentioned, that have only used real stag, no imitation stag. Also look at Schrade's Uncle Henry knives, they are a good example of fake stag. And a lot of the newer Kabar knives have fake stag (they call it Ka-stag). If you can look at a few examples of real and fake stag, you will quickly realize that it is easy to tell the difference.
