Snap On ACT 2500 and ACT 3000-I have them both-can I charge with them?

I am always looking at craigslist ads and along the way I have purchased both a Snap On ACT 3000 AC Recycling machine and a Snap On ACT 2500 AC Recycling machine. They both turn on when plugged in and both have very heavy canisters underneath. All of my cars have factory AC, all still working and all still on R12. Question: Can I use either of these machines to re-charge when the time comes that it is required?
Thanks
Norm
Norm