5 Cent Third Issue Mystery Plate R137

I just started to plate the 5 cent second and third issue revenues R107/R137. The Boston Book shows the second issue R107 was printed with plate #19 . The imprint and plate number is at the bottom center of the sheet. The Boston Book shows the third issue 5 cent stamp was also printed with plate #19, but states there were 2 plates made for the third issue stamp.
I have large enough multiples of R107 and R137 left column stamps to prove they were printed from the same plate. (Left column stamps have a clear dot over the "S" of US at the top left corner. I now have a left column strip of 20 R137 with different transfer dots, indicating it comes from a different plate. Does anyone have any imprint copies of R137 showing a plate number other than 19? Does anyone have a proof sheet or copy of a different imprint.