Yes, that is true mostly. The problem as I found out when I sold some proofs at Spink not so very long ago is that the prices were a bit UNDERWHELMING and less than I would have been able to sell for otherwise, and had to subtract out shipping, insurance, and commissions not to mention all the other sundry charges. The two matrices you showed would likely not attract a lot of interest, the crown moreso though sadly lacking a date and being only the rev. trial. Another thing the RM did was to mark/inscribe or number specimens and then either leave them that way, or heaven forbid, SCRATCH out the details. In fact, I have a pattern 1951 where they did just that - yikes! Your firstmost piece appears to show some rough handling as well and was lucky to slab as a "62". In general, the more valuable bits are either those with complete obverse and reverses with date or second choice either the obv. or reverse complete with the designation "MODEL" on the opposite side.