Welding Tips and Tricks

I am interest in what this thing is. It has a graphic " The Bug". A little “google” work tells this it may be from P&H Gas Welder Generator or Chemetron

I think it might be pre 1970s, and maybe military surplus. (WWII??)

What I would like is:
- A manual
- Any guesses for age
- What does it do? I guess it is a stick welder, it is gas engine. Does it have a battery charger or 110V power?

I am not imedeatly looking to sell it, but I would like to know it value (For example if it is worth $1000, it would be a sad day to sell it for $100)