Can I just say, as a random aside? It's funny that nobody in the entire wasteland has a single gun from Egypt's past. Stalker can get a whole Ford pickup, the Mutants can live in a Fallout vault. But nobody's packing heat.
I brought this up abt a yr ago. Forget now how it all played out, but you are "bang on target": a well-oiled, and properly STORED firearm should be a LOT more out-of-the-box ready to rip than a car or truck. It's a much simpler overall tool with FAR less maintenance gotchas than an automobile.
Rubber HOSES (including wiring cladding), and TIRES will be iffy after only TEN OR TWENTY years, and it's been FOUR CENTURIES.
Only issue is possibly POLYMER guns, or even just polymer lowers on rifles (etc). Steel should be fine if oiled and stored, but poly guns? IDK.
Ammo might be createable, at least by the decayed, and we clearly see they have shotgun shells, but where are the shotguns, themselves?
And where are all the guns on the MILITARY BASE the mutants live in? Bows. WTF.
The inexplicable universal disarmament back to bows and blades in a modern combat environment resembles the new era of Tomb Raider robbing Lara Croft of her iconic twin pistols/mini-Uzis/MAC-10s. Given that Shani is a stand-in for the newer, weepy-er Lara of the reimagined "survival play" Tomb Raider (OG Lara was an icy b1tch and total boss with clear ASPD traits) , it kinda fits that source, but it's jarringly weird.