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I have seen this on 4300 carbs (with it's own bracket in front of the primary linkage), but not on the 4100's. The comment is just enforcing what would be concours correct, to be helpful, not offensive.
For reference, here is a factory correct return spring setup:
Finally found the NOS choke kit I was mentioning. This is labeled as an acceleration modification? So it is not factory but does clearly show that they added a spring to the pump lever on the 4300 model carburetors. So in some sense I guess some of them did have a return spring upfront although comparing a 4300 to a 4100 is apples and oranges. Just thought I'd share .
You probably already know... that return spring is not used from factory, original, or correct.