[Xlot]

As far as I can see in the early cars (pre-82) pdf from Porsche, they're different.

There are three different fuel pumps found on early cars, in combinations.

The early 78's I think don't have an in-tank pump? (Looks like '79s do tho')

The different fuel pumps I can see are:

911 608 102 00
928 608 013 00 (in-tank pump)
930 608 113 00

Go to the "Service" part of Porsche's website and follow the links for parts catalogues to find same - the diagram is a mess for that page because of the massive variation between those first few years.