I don't think it is over gassed and have never seen an indication there is an issue. But with the price of IMI Galils today, it's cheap insurance. This one sits in the back, I do not like the AK bufffers that since on the recoil spring unit.
I assume original Galil?
Proper insurance would be a KNS instead of a piece that can and will fail AND is difficult or impossible to source. Just sounds like a recipe for disaster to me.
I understand how and where it attaches. I've spent time building galils and enjoy them very much.
AK buffers do not interfere with the spring in any meaningful way. The spring assembly is just a handy place to attach it so it doesn't bounce around inside the rifle.
What these buffers do do is artificially reduce the distance the bolt has to travel and directly transfer recoil to other parts and your shoulder which may not be an issue without. Long bolt travel without hitting anything is a key to smooth recoil. My AKSU with KNS can be set up to never bottom the carrier out which has the advantage of basically zero recoil. Sights don't even move. Carrier never hits anything in the rear of the receiver.
IMHO, for a machine gun forum the Galil, unless select fire, is pretty cheap even compared to a MAC. I still beat on my saigas as often as I can. Hell, my AKSU is worth well more as a cut apart kit than I have into it with stamp. You can either set it up so you can enjoy it or you can set it up for someone else to enjoy and if you set it up for someone else to enjoy, IMHO, might as well sell it.