The Camen G27 chassis of similar vintage had the same nose and 1-piece .062 main rail, but the inner rail was .055, IIRC. It also had pan hinges in addition to the plummer. I had a least a couple of those and 3 or 4 of the chassis pictured above. I also remember a similar one that had a steel winged nose. We think of Camen mostly for motors, but there were some interesting chassis and bodies, too.
It's a great chassis from the period. That main rail made it pretty hard to knock the axle tube out of it. Yours can use some TLC which I'm sure you'll give it. It would look extra nice with a set of 1/2" Camen purple front wheels.
Looking at the photos further, I think those might be the 1/2" Camen aluminum front wheels. I thought at first they were the 5/8" Parma's, but now believe they are 1/2", so could be any number of similar fronts.