Never heard of R22A. Usually linesets can be reused provided they are in good condition and proper size. If you switch to a new refrigerant, R-410A for example, you'll want to flush the lineset well or replace it altogether.

Sharkbite fittings according to website is for hot and cold water distribution systems only. They won't work or hold for refrigeration lines.

The fact that you considered these fittings and listened to a uninformed salesperson raises the big question, how do you intend on recovering the refrigerant, performing a proper system evacuation and proper charge?

The present refrigerant in the system is R22A and doesn't need recovering. The system had almost no pressure and I re-charged it with R22A three years ago. I has worked flawlessly ever since and no leak seems to be present. I didn't completely trust the salesman, that's why I asked the question here. I do think the R22A improves the performance of the old heat pump and the only reason I would want to change it is improved efficiency due to the variable speed blower and the scroll compressor of the new units.