According to
http://www.nostalgiaair.org/Resources/504/M0039504.htm the output tube is a 171A. They're getting to be a little pricey. It's a single ended output and I don't think a 171A is going to excite any audiophiles.
It's a nice TRF set and I hope that you or someone restores it. I'm afraid I don't know anything about the company's history.
John