I'll be honest with you. I've been around,
& seen alot of old wreckers, but never seen one quite like that one. If I could see it in person, I might be able to help you figure it out. Looks almost like it was made from several different units. The service body reminds me of a Hubbard Wrecker, the booms look like a Stringfellow, & the mast portion looks like an old Ashton unit. If it were me. & wanted a Wrecker, i'd look for a period correct Holmes unit. They were more plentiful, & parts aren't too impossible to find for them.