Personally I'd leave the Stab Wound on the finished Mount...thats what gives a Deer their Character in my opinion!
My Taxidermist supplied me with a *Free Cape and all I had to do was find a replacement Cape for it in the next year or 2...a Hunting Budy shot an Odd-Racked Buck and gave me his Cape and I was back at the Taxidermist with my replacement Cape that same year!
The reason I had to get a new Cape was someone had shot a very nice 10-Point Buck I had trail camera pictures of said Buck for about 3 years of Him growing over that time period and I had Bow hunted him that last year.Well as stated someone had shot him during the Nov. Rifle Season and I found him dead on our Farm 3 months later and he was pretty well all Skeleton except for some hair on 3 of his legs and a little on his head so I called the local Game Warden and got a Permit/Reciept to keep him and decided to have him Re-caped back to his former Glory!