When I replaced the rear trailing arms in my 91S, I installed them but not really tightening the forward bolts, and then set the rear hubs on blocks to load them into road height position, then tightened the forward bolts, thus reducing the movement stresses in the bushings. The rear long bolts I didn't worry about (lol, lazy).
However, I did slather the long bolts with plenty of anti-seize goop, still pristine from new.
1989 Milano, Shankle Sport
1991 164S, stock
1994 164LS (~Q)
1972 Morgan 27
previously owned since 1964:
62 Morris MiniMinor 850, 67 Austin 1275 Cooper S (Downton 3/4 race), 64 Giulia Sprint GT (1st red one made), 72 Fiat 128 Sedan, 75 Alfetta Sedan, 78 Alfetta Sedan, 78 GTV, 81 GTV6, 86 GTV6