Bob, Unless the gun is otherwise pristine, IMO, the collector value was damaged by the addition of the Nydar sight. Removing it and plugging the holes with headless screws will be the least offensive "cure". We talk of "collector value" rather glibly. In reality, most of the real collector pieces are already in someones collection/museum. IMO, a true collector piece should be 100% correct, have great provenance, and be 98%+ CC intact. Best, BILL