the later 'specimen' sets use a specific die that changes the appearance of the coins - but before that started the specimen strikes of circulation coins did receive better QC than a circulation issue - you will see it mostly in the fields of the coin - they will tend to have a polished appearance, while high grade circulation strikes will be shiny, but not have the polished appearance;
I believe that the specimen strikes used a combination of higher pressure, higher quality dies, and slower speed.
What I find confuses things ALOT is that the
RCM has shuffled the names of their sets.
While I was growing up there were actually three sets:
1: Proof set: highest grade coins, encased in black leatherette case with a silver dollar which actually contained silver; all coins have select satin finish; comes with specification card.
2: Specimin set: these were circulation issue coins with a higher level of quality than the actual circulation coins; came in a sliver cardboard box, with a blue booklet, and each coin in a separate case c/w spec card - to be assembled by recipient.
3: uncirculated set: this was circulation strike coins placed into a polyfilm package, placed in an envelope with a specification card.
I don't know for sure exactly how many sets are now being made, but I know that the 'specimen set' moved to a case and packaging that resembled the Proof set;
The proof set is now offered in at least two varieties;
I believe it was 1998 when the specimen coins first all received a specific lined "matte" background - which they still do;
At some point the 'uncirculated set' started to be called a specimin set, and then they were being called a 'classic set', and now I think they are back to 'uncirculated set'.
Somewhere in the mix they started offering sets in cardboard encasement, and even encased in mouse pads!?
It seems to me that the
RCM is changing the number of sets offered almost every year.