I would fill the holes too. I had this same question about my 70 blazer. It was a 307 originally, so it only had a K/5 emblem then the 4 wheel drive emblem under the side marker. Then of course the CST on the doors. I now have a 350 engine in the blazer, but I decieded to just keep the emblems stock and not put the 8 350 under the K/5 blazer emblem. I think it would have way too many emblems with the "8 350" under the K/5. Just my 2 cents