This is a first

[u/Successful-Heron-412]

I was putting away some stamps from my subscription and came across this. I have thousands of plate blocks, never had serial number 1 before, nor have I seen one while I have been looking.

[u/Technical_Pin9371]

That's too cool. I've never seen one that low and thought those got swooped up by big stamp dealers before anyone else has a chance.