Two people really wanted it in 1997; one of them is not bidding this time?

I wouldn't rely on either of these examples as a bellwether.
Errors ebb and flow. A good percentage of collectors have little to no interest in errors.
Scott doesn't list "no gum" pricing for the France pair, while offering "no gum" pricing for Sc#3 and other Sc#3 varieties. No gum is around a fifty percent hit off of catalogue value, give or take, on the other Sc#3 listings.
If "no gum" is the expected state of Sc#3c, Scott would say so (I would expect). I don't see a note for "no gum" in Yvert or Maury, either.
We all know collectors, some of them hang out right here, who would say that "no gum" is a glorified spacefiller.