Paintball co2 tanks

[Bamsdealer]

Checked my parents basement and found a couple old co2 tanks from the early 90s when paintball was just becoming popular. I think they're about 7 or 9 oz and probably steel or thick aluminum. They're covered in a bunch of spraypaint Does anyone know if they need inspected before a co2 place fills them? Trying to figure out whether its worth my time rigging something up. New 20 oz tanks only cost $20. It would be nice to have them for purging hop bags and the occasional picnic

I see homebrewing.org has a paintball regulator for $50...

 

[smooth]

Yes, they have a five year hydro-retest interval.
I have been using a paintball 20oz cylinder with my jockey box.
My two paintball tanks are new enough, and I have not checked into the cost of hydro testing yet.