Many thanks for responding to my query.

Currently looking into this in more detail.

My car and one pictured are pre-facelift Mk3s (German built Ghia and XR3) and I can confirm these holes are not on post-facelift Mk3s (i.e. revised shells made post 1983 with the single-bolt front shock mounts).

Further the holes in my view are too tidy to be non-factory and possibly would have required a very accurate press (but I am quite happy if someone has other evidence and pictures).

I am only talking about Mk3s because the Mk4 shell had many (some more obvious) revisions and I know they are not found on Mk4 shells.