Every once in a while, like now, there is a "customer service" issue on a firearm (one on a RAMI now in the CZ forum, for example) where there is a problem with a firearm and the approach could be "Send it to the manufacturer" for repair, etc.  Turns out there are flaws of some sort and the response is, replace it.  We don't go through DROS, 4473 typically on a gunsmithing action but if the manufacturer/importer wants to solve the problem by replacing the firearm, what happens to facilitate the return?  New firearm, new serial number, and if it's a CCW piece identified by ser. no. (as in Ca.) what hoops are jumped?  It seems like in my county, "new" adds to the CCW are only done on the renewal point, not in between fromal renewals.  So you'd likely be out of service on that one?  (I'd ask the "Sheriff" on that, too, if the issue came up, of course.)