You need a special license/certification to buy R12 in the US. It's not difficult to get the license. You also need special equipment to charge your system. If you need to top it off, you'll need a gauge set and the specs. If you need to fill it from empty, you'll also need to find and repair leaks, replace the dryer, add the proper oil, evacuate the system, weigh the amount of charge, etc.

Sixto
91 300SE
87 300SDL
83 300SD