Well i don't blsme you on the treestand, always best to try it out in good light and in a safe place, but make sure the tree is of proper size, not too small
and yes it sucks to find them missing parts, been there with many a ladderstands over the yrs, very fustrating to say the least!
I ha e found the brand you buy can effect how common that is too, highrer end stands have few if any bolts on climbers, but sure it can happen with any brand
as for not finding the stands, well if someone took them, then, that says what I figured, people trespass and hunt there without permission, very common deal by me, sucks, but can still be a great place to hunt
and in all honestly, its never a good idea to use a stand blindly, not knowing its condition, age or how safe it is, best to check them out in good light
and again, just cause its public lands, doesn't mean there all crowded, i have hunted many great public lands even on opeing day of gun season and had the area to myself, public lands can be as good as any place to hunt
and last, don't give up, i been on good land all week and not seeing any deer, so it happens