Got 2 free tanks, are they useable?

[oxyhacker]

1941 is probably an 1800 psi 38 cf, 72s didn't arrive until early 50's or so and were actually 68s until they bumped the pressure rating to 2250.

 

[pescador775]

The yellow tank is junk which I wouldn't touch. The galvo tank can be saved, probably, and you may wish to do so. A note about the hydro stamp, 2SD83. It is probably genuine. Up until 15 or so years ago, the authorized stamp included a short letter code for the hydro facility. After that time, the Office of Hazardous Materials Safety mandated a four digit alpha numeric system which is stamped in a clockwise fashion.