I have this plastic M35 rooftop, I've never seen another like it and I can't find anything in the internet like it
I had two of them... Both were moulded one-piece fiberglass units without rear window opening.. One was more rugged than the other.. One was on a 5-ton M51 and the other on a deuce, M49C.... Both of them were of different manufacture design and about 4 to 6 inches taller than yours all around, but still in military style .. Yours is a much-better look, is very close to ragtop height.. The height of the one on my M51 created a clearance issue with the cab protector (oh the irony

) .. It would smack the top of either rear corner of the "hardtop" when the dump box came down if truck was on uneven ground.. The one on the M49C had raised flat spots along the front edge for clearance lights and went higher than the one on the M51.. Looked like it would be a good style for a G749 (jimmy) truck ..
Sold one last year, and long-ago traded the M51 one for a brand new ragtop and hardware.. I spotted those "hardtops" on those two trucks in the early-1980's about 10 years before I bought the trucks.. An old friend of mine said he knew a surplus dealer (in NY, I have his name) had a bunch of these aftermarket ones for sale at one time, but that was his hear-say , and at least 15 years ago

