Lug-centric to Hub-centric? Options

[gord]

I'm in the process of getting a 1972 safety certified (for registration in Ontario), and the inspecting mechanic has raised the issue of the lug-centric rear wheel design. While I'm pretty sure he's going to issue the certificate based on the fact that this is the way Porsche sold the vehicle in 1972, he has opined that changing a flat tire at the side of the road would be difficult or even impossible with this design...

I understand Porsche did change the hub/wheel at some point, so I guess I'm wondering if there's an option of "upgrading" from a 1972 rear hub to a later model year that would provide an easier way of centring a wheel on the hub? Or did the rear wheel design remain unchanged throughout the entire production period?

Any insight here would be appreciated!