I got some cheap Chinesium units off Amazon a couple years ago just to try it on my Harley, simply because I'm chasing a strange electrical gremlin that's allowing my headlight to overheat with Halogen bulbs. I was melting headlight sockets, even burnt the heck out of a ceramic pigtail socket. Anyway, mine has the plastic lense and the bike has been outside for the better part of 2 years and no fogging yet even though I expected it.
The brightness and clarity compared to all the old halogen bulbs I've tried is amazing. So much easier to see at night. I would definitely prefer a glass lens and will probably switch to one eventually, but for now it's doing fine. It also runs a TON cooler than the old halogens. If I'm remembering correctly the new LED sealed beam had a heat sink in the back of the unit, because I thought "how is this supposed to work at cooling it when it's sealed inside of a chrome headlight bucket, but it actually works just fine and stays nice and cool.
As for the truck lights, yes all the 70s trucks, cars, and vans used the same exact sealed beam bulbs. That meaning that if it's a 7" round, a 7" round bulb from Ford, Dodge, Chevy, even Toyota will all interchange. Same goes for the rectangular bulbls. Universal fit. You just need to cross reference the bulb number or measure it.
Here is a link to the one I put on my Harley, even though it's 5 3/4" round, it still will give you an idea of the materials and price to compare with.Headlight Link