Although PROJECT: SUPERPOWERS shows Green Lama running around in the 40s with a bunch of other super heroes, he never actually met them back then. Mostly because they were all published by different companies.
But he was involved in a very-brief team-up with his co-stars in PRIZE COMICS.
Along with Green Lama, PRIZE featured the super heroes Black Owl, Yank & Doodle and Dr. Frost; the funny-cartoon characters General and the Corporal; and the monster of Frankenstein.
In issue PRIZE COMICS #24 (October 1942), Dick Briefer (writer/artist of Frankenstein) decided to gather the heroic cast of characters from PRIZE together and pit them against Frankenstein (why he included General and the Corporal is a mystery lost to time). It was an 8-page story that didn't feature a lot of organized teamwork. And despite the final panel, they never returned; at least not as a team. This was their one and only get-together, and it wasn't even deemed important enough to receive a mention on the cover! Definitely not a threat to the popularity of the Justice Society!
Without further ado, it's Frankenstein vs. the PRIZE Fighters!
You can download PRIZE COMICS #24 and lots of other awesome golden-age goodness from Golden Age Comics Downloads!