That appears to be a late IIa. The firewall is a key indicator as is the metal grill. Frame rot is common, galvanized chassis are available new!
If you could get it for the right price (i.e.- Almost nothing) and everything else isn't too bad, then swapping the frame might be worthwhile. (At least as long as you don't try to figure in the value of your time.) I'm sure most of the rest of you guys know better than I, but I've heard that once you've got a rolling chassis, the Series trucks are relatively simple to disassemble and reassemble on the new frame. (That is, '
simple' compared to something like my D2.)
I love the later IIa's, III's, and even the 101's. I just wish I had the time and $$$ to take on another project.
Hopefully someone will pick this up to either restore or part it out so that other Series trucks can continue to live. I'd hate for it to sit in that trailer park until someone realizes it's built of aluminium and decides to turn it in for scrap...