Based on my use of my SBR'd Scorpion for 8-10K rounds mostly suppressed, there isn't alot one can do to hinder it's function. The bolt makes up a good portion of the gun's weight and is a massive chunk of steel. I rarely clean or oil mine and it just runs. Maybe check for any cracks and function test on/off safe. Grab a new recoil spring for the heck of it from CZUSA and be done with it.
Hopefully it's a great deal as the new ones are 750-800 at LGS near me.