273 rockers on 340 with hydraulic cam

I don't see any cupped washers, unless you mean the washers on the mounting bolts; In which case, those are sometimes used for geometry correction. But as you may have noticed, those rocker's need matching pushrods.

Going back to the cupped washers, if they are ordinary washers, with the same thickness in every direction, then they are some-one's bandaid and should Not be reused, because they cannot simultaneously fit both the saddles and the shafts and so they are somewhat unstable in the lateral direction. And very possibly the tiny bolts will fatigue and possibly come loose under the bending forces, that may come with much more than 318-type valve springs.
There are proper washers and Geometry kits to fix geometry errors, which in the Mopar camp, are common..