A silver dollar collection was found and the executors want to inventory it but two of the beneficiaries are objecting is it acceptable for the executors to inventory it anyway?

The beneficiaries have no authority as to how an estate is to be handled. That is the duty of the executor or executrix who will be held personally and legally accountable to the court for all assets and property belonging to the deceased. Therefore the executor has a legal obligation to inventory ALL property and assets and to accurately enter them into the probate filing of the estate.