The liquid strip is the most gentle on the wood. The glass bead would be gentle but thorough on the rust. You might need to do some oil soaking of small parts like screws first. Just a dap will do. Wish I had that here, I could get 'er apart. Then it could be seen. The bayonet boss' bottom screw is holding the piling swivel in place so there's only the transverse screw remaining. You have a nasty lift in the upper handguard too...at the rear. I've also found for removing hard screws...work the screw driver into the slot and clean the rust out. Then with a properly fitted screw driver, rap the screw driver smartly like a punch and it breaks it free. You can usually turn them right out. If not, more oil soaking.