Mk1: Modifying uprights for CAC9938

Has anyone tried to fit later CAC9938 upper ball joints to early Mk1 uprights (instead of 14-4008-1) ?
I see different taper in the hole, so upright would have to be slightly corrected with a reamer (7+ degree, i.e. 1-1/2" per foot taper, i.e. 1:8, as of my estimate).
I know of tiny difference im upper arm mounting hole spacing but this millimeter is file-able.