Motorcycle shock oil is popular, but any non detergent oil like hydraulic oil or power steering oil will do.
I am no expert, but many years ago, I did have a bunch of '51 and '52 shocks apart. I found that as long as they were kept wet inside they were probably able to be rebuilt. With the front shock you had to cut the wish bone and pull them off of the "axle". The seals were common seals. There were differences in the port size in the piston between cars, not terribly important. I remember the biggest problem with the front shock was on the under side there is a plug, similar to a freeze plug, but not! I had to build a couple of plates (sized on a lathe) and sealed with rtv gasket silicone. I used a chain wrench to remove the piston caps.