74 Duster, full build 6.4 conversion in Australia, rebuilding front end questions!!

If you are talking the LCA pivot pin, then you are fine to re-use as long as it isn't bent. The factory one is a nice forged piece.
Yep thats the one, as for what they cost rather get new mirrors lol. As this car pretty much every part either brand new or reconditioned. Hopefully all worth it haha. Watched a few videos on rebuilding the arms so i will do this soon.