Chances are the JY pieces, free or not, may be in the same general condition yours are.
You may have to pull a lot of them until you get a decent set but it may be worth it.
Buy a "Thread Chaser Tap” the same thread as the bolts; this tool will allow you to run it through the Nut portion of the mounting hardware and then use a good anti-seize product on the threads.
I use a Copper anti-seize product all the time and I do not have a problem with any bolts coming loose, just in case you were thinking that.
If you need to or feel it is necessary, consider a Nut on the end of the bolt but do not think it is.
4x4, 5sp, Std Cab, Stepside, E4 Red
4” Lift - Coil-Overs, 6” SkyJacker Leafs - No Blocks (Mistake)
31 Spline FX4 Rear Axle, 4.56s and OX Locker, Hurst Shifter w/Optional Stick and "Made by Grev" alignment adapter