With a GI stock you will have a gap where the selector switch went.
You can leave it, fill it, or put a dummy selector/lock in there.
ETA: I can't remember who is making the current production SAI wood stocks, but I've seen many recent production guns that are coming with really nice looking stocks.
Here is my Tanker (pretty much a SOCOM without the optic rail, in a standard SAI M1A stock. This one was really good, and had been lightly treated with Tung oil. I've worked it over a little more. The standard stocks don't have the selector cut out like the GI stocks. You can find some really nice GI stocks in the EE or similar on the M14 forums. I got one that looks like it was barely even used.