Don't use a doe form, does and bucks are not the same and it'll show. There's no reason a form can't be shaved down to fit, but my suggestion would be to use a different cape. Unless it's something special, it's just hair.
I just noticed the picture you posted. That's a great deer, but man, he's ugly! A new cape will make him look like he should look. To mount it like he looked when you shot him... well, I really think you'll end up regretting it. It just won't look right. But, HellsAngel is right, you have to look at it.