Ask yourself the following 2 questions:
1> Am I going to be satisfied with the way the pump looks 6mos, 1yr, 5yrs from now?
2> Does the condition enhance, coordinate, or elavate the other pieces in my collection?
If you can answer Yes to those two questions then don't restore it.
If you answer no to either of those, then the question is partial or full restoration.
If a sympathetic restoration can change your answer to yes to the above questions you might go that route, otherwise go with a complete restoration.
The saying 'It's only original once' is fine when you're talking very rare pieces or pieces whose appearance condition is better than 75% 'day it was installed'. Otherwise some bit of restoration is worth doing.
Looking at the pictures you included I'd work on those door panels and see if you can reduce the running surface rust. If you can restore them to at least 80% white I'd go that route.