If an engine is knocking hard enough to make the distributor cap move, don't lean over the fender without a ballistic vest on- - - - -it's about to start throwing pieces in all directions. That being said, any rocking motion between the cap and the housing is too much. Either find a better[fitting cap, ort make that one fit correctly.
What's a stovebolter doing going to a "restoration shop" for a tune-up in the first place?????????
Jerry
