Waow thanks for sharing these pics and the link !!
I think we may have an answer. It seems that's it's not only a safari / not safari question but a 92 or 93 question !!
All the 92 cars seem to have your PE fuel tank design whereas 93 cars seem to have the Tamiya part fuel tank design, even if it's not exactly the part visible in non safari cars, and as safari cars had a fuel fill through the rear wing I suppose the tamiya part is correct for Safari version (92 or 93) but not for other 93 events.
If I'm correct that would mean than we don't have the perfectly accurate part to build the 93 MC fuel tank, but tamiya would be the closest one in this case.
The PE part is perfect for any 92 version except safari.
That's my conclusion, but it's not sure !!
K AM 7562 (last pic) is a 92 car and it's the one Jonsson drove to victory the following year in Sweden.
K AM 9821 is a 92 car judging by the livery but I can't identify the rally (registration is closer to 93 registrations) and I'm so wondering if it's not a replica car or an historic event picture as we see a Porsche Rothmans service van in the background whereas no Rothmans Porsche drove in 92...
that could explain the strange registration on a 92 car. In fact it's probably a 93 original car rebuild with 92 Sainz livery.
But nothing is 100% sure.
I will build my 92 MC car with your PE fuel tank for sure, and probably my 93 MC and Safari with tamiya part if no more information till I build them.