We can posit that certain plate varieties of stamps should theoretically exist, however until an example turns up in the wild, any discussion of rarity or value is moot.
For example, many of the plate varieties on Scott R15c (1st issue 2-cent USIR) should also exist on R15d (silk paper), differing plate states and printing timeframes notwithstanding. Varieties of R13c (2-cent Proprietary, blue) may exist on R13d (silk paper), R13e (ultramarine), and R14c (2c Proprietary, orange)... and the list goes on.
For several years I've been enamored with the major double transfer on the $500 Alexander Hamilton documentary of 1917 and its various overprints and serial number color variants. I've been maintaining a census of the reported double transfer examples (
https://revenue-collector.com/hamiltondt/) and also keeping a spreadsheet of non-DT serial numbers to try and narrow down the range where the serial number colors switched from orange to red early in the process.
I've submitted additions to the Scott Specialized Catalogue fleshing out the listings of orange vs red and listing double transfers where applicable. Up until now there have only been two of the variants that have not been reported with a double transfer:
1. Scott #RD65a: "Stock Transfer" overprint with red serial numbers, handstamped "SERIES 1940" in large black text. An extremely rare stamp in its own right, currently unvalued in Scott even without the double transfer.
2. Scott #R249a: No overprint, orange serial numbers. This should not be a difficult stamp to find an example with a double transfer... at least not as difficult as it has been. The base R249 with red serial numbers catalogues $50 used, $85 with double transfer, and the base R249a with orange serial numbers catalogues $65, so not exactly a scarce stamp. I had identified a range of orange serial numbers for R249 from 1,707 to 2,032, and red serial numbers from 4,580 to 54,608. This puts the maximum number of orange serial numbers at 4,579... at least until additional examples narrow the top end of the range further. (All of the orange serial number variants are undervalued IMO, at least with respect to their populations compared with red serial numbers.)
Fast forward to last week, and lo and behold what should appear on
ebay, but the first confirmed example I've seen of R249a, serial #152. It was a best offer situation, so I made an offer and we ping ponged back and forth, but I wasn't about to cheap out too much. Yes it is punch canceled, but beggars can't be choosers.
Now there is one... hopefully there are others to be found.
