I completely agree that replacing the wood furniture with plastic is an upgrade for a rifle that will be used as a complete tool for an un-determined amount of time. As long as it is N0T a folder or a T6, these types will break and strip out with abnormal use. a nice ATI Monte Carlo or Chaote, butler creek conventional will suffice greatly. You all must remember that SHTF does not mean an extra hour on the range, it means you can die in 5 minutes, 5 days, 5 weeks, 5 months or 5 years. Your choice gun has got to be able to handle the abuses of being both a firearm and a tool without you running back to the garage to fix a scratch or apply tru-oil and lube. In SHTF, that pointless BS has no place. I do not mean to say that wood is inferior because I am one of the stubborn bastages that thinks wood, steel and leather make a true firearm but if you have the option to do away with the extra negatives of worrying about wood damage then why not?
The SKS in my opinion is the best SHTF choice even better than the AK, everything the SKS needs is on the rifle and you don't have to hope Aim still has mags and they'll ship to your bug out cave all while the world is lawless and death is everywhere.