Any QD mount will fir as the older 458 is a shorter action than the new ones. Yes you'll have to drill and tap for the QD's. The d&t is for the base that the QD's will sit on. The other way is to machine dovetails on the receiver. Like I said, I haven't mounted mine yet as I'm up to my ass in crocs and alligators for the present. I think a good peep would be another alternative.