Depends on how old the coat is and how it was stored previously. You can judge the quality by gently weaving your fingers through it and see if hair were caught. The amount of hairs you get should tell you teh current state of your coat. Beaver has short hair and just like any fur , its quality is also determined by the skin. At times, older fur's skin tend to become brittle. I bought an ancient chincilla. Extremely beautiful from an estate sale, but it tore after a few wears.
Personally since my chinchilla cost about 500 dollars, I'd leave it to the professional. But I havent done so.
If you feel s0-so with your beaver, I'd suggest you buy the thread used for leather. Soft ones... You can get it at any craft store and sew it up.
It also depends on how big the whole is. Remember, fur goes with your movement. that's why they make it bulky so it wouldnt tear if you happen to sit on it. . If you sew it yourself and then happen to tug your jacket while wearing it, you'd end up with a bigger hole.
Moi, December 2008