I think you're good making a more informed attempt at removing the old style nozzle plates and installing the newer style with your fresh injectors. I looked at the angles that come up against the pre-chamber on both styles heat shields and I can't see a obvious difference. Plus, there's Diesel911's post #16 in this thread that mentions changing over to the new style but does not mention swapping out pre-com chambers for a newer style. Seems likely and more economically sound to update the seals without changing the design of the pre-combustion chamber.

OTOH, I myself have installed injectors on top of these old style nozzle plates without trouble. Could buy you time, at least. And you could test for compression leakage past the nozzles post injector install by squirting soapy water around your injectors, with engine running. No bubbles = good to go.