Definitely XXX is the one to seek the advice from. We're all still learning stuff every day though. We always assumed the Claycos were new manufacture. Then one day Pat Adams bought one and it had the telltale remains of a triangle stamp on the left side of the receiver. You had to know what you were looking for, but it definitely was there.
Those came into the US in the '84 timeframe. By the time the '88 to '94 prefixed type 56s came in we have some pretty good evidence that they were consistently scrubbing old guns, reassembling them into new stocks, and refurbishing them such that they looked new. Long lug, Short Lug, or pinned barrel all showed mixed together with a variety of 'matching' supporting parts of all eras. I find it a hard sell to say that all, or even a majority of the Ms, Ds, NRs, Sporters etc. are new manufacture when so many other guns of the period are scrubbed for resale. Anything is possible though.
We may never truly know the answer, but that's pretty much the purpose of this forum: to discuss ideas and theories in a civil manner (w/o getting wound around the axle) and see if we can come to an agreement based on the evidence we can produce.