I thought I had one of those like stampdog and philb shared but it seems mine is a tad newer (just a guess). I don't know much about revenue stamps but in looking at the design I can assume the date is supposed to be hand written with a signature applied. Either there were varying rules or the rules were loosely applied as both of the first two don't appear to be dated. It's possible that stampdog's was but maybe the ink has faded, hard to tell. I also notice philb's has some extra purple cancelling? Anyway, here's mine:

OG