R338 In Greens Stock Transfer Mixture

Found this stamp in a greens mixture of about 1000 stamps that was all over the place with duplications and condition. this stamp and a few of $1 to $5 dollar cat. and a cut cancel RD260 with serial # 7015 greens all used for $20.

The R338 has a 3 wavey line cut cancel and what I think is a low serial number of 10. Were many sold? just wondering if it is a low serial number. Anyplace to research that type of information?

thanks for your time and assistance.

Respectfully,
RIchard

Low numbers usually mean a fairly scarce stamp. Uncut examples are very scarce, with a cat of $1500 but cut cancel examples only cat $125. Still a nice find in a $20 mixture. Ten is clearly a very low number; they started at 1. They were issued in vertical panes of four.