Reviving a 44yo ac system tips ???

As far as I know there are no specific O ring kits available for these old systems. There are master O ring kits but they would be a bit pricey for what you want. You only need a few rings. I would collect all the O rings in the system and take them down to the local parts place and match them up from their master kits. Make sure they are A/C system rings, R-134A compatible and not just general purpose O rings.