air conditoner guy advice preferably from a hvac or someone with knowledge of this.

I expect that after the units had its Freon reclaimed, the operator has to 'Tag' it with identification etc etc.

Also I have found several Heatpump units with the Freon still in it. There's a tap they close off and then they undo the connections to the joining pipes, and remove the outside, or inside, or joining, unit.

Also, I have tipped over fridge compressors that have sat there for days, open to the air, and suddenly had the oil squirt out under pressure, everywhere, very messy, expeshly when it happens inside.
There's one way valves inside it, they will hold pressure for quite a while.