While it IS true that you shouldn't swap bolts back and forth (some folks will buy two or more uppers, but only one bolt/carrier assembly), you can obviously replace a damaged bolt with a new one without much worry.

The problem is that the bolt you're describing is NOT new, and *could* be worn enough that it exceeds headspace dimensions when mated with your barrel's extension.  You need headspace guages to determine this, and if it DOES exceed headspace, then the bolt needs to be tossed, and you need to buy a new one.

-Troy