FYI...
- I had a double set of aluminum 50s from about 1972. They were gray with the blue aluminum decal but did not have the Chevron. I remember they came with a red O-ring when they were new and that blow molded backpack with the Black harness with yellow pinstripes and nifty D-Ring shoulder buckles. The tanks were like brand new... I hardly used them in all the time up to when I got back into diving in 2011. The tanks were the 6498 aluminum but they tested VIP'd OKAY until last year. The one of them failed the Eddy test and I decided to retire the other one along with it. Such beautiful doubles... It sure was a shame to have to retire them.
- On the other hand, BRAND NEW Aluminum 50s can still be purchased and they're made out of the modern aluminum. My buddy Rich has just purchased his 2nd set of these and is planning putting your Decals on them when his project is done!