It says made In USA.
I was thinking along those lines but Stanley usually had their name etched on the blade instead of just saying USA. I found a Stanley plane guide that was excellent for dating plane. Try this link as a fast way:It's a copy cat plane, made in a new city in China - USA, OYVAY Province, China. They'll do anything to cash in on a potential market.
Looks like a Stanley #5.
Lie-Nielson as well as I have the No. 3. This looks like a pre-Stanley Bailey.I have a #5 that isn't marked too. I think everybody copied Stanley back then and in fact still are. I know Lee Valley studies them to see what their shortcomings were and then modifies the original.