Meh, that sucks, but it doesn't matter, that's a nice Type 99, with early features....hell, as 1srelluc brought up, a real dustcover alone command $150 - $200 nowadays (he said $300...maybe but that seems a bit high to me...).
In any case, it looks like original finish, and it doesn't look sanded...its just a bit on the light side...try to get me a good sharp pic on the left receiver side with the s/n and mark in front of it, and I'll look up the series info for you later on...
I don't remember exactly, but there might be a possibility some early 99's might be matched by assembly number...I know Type 38's were assembly numbered (which means there would be an assembly number on the under side of the receiver, which you can only see if you take it out of the stock...bolt and receiver were matched by those numbers...).
Again, I would still consider it a keeper, nice gun, IMHO...