It depends on what you are using for reference and what version of Boba you are doing.
Magic of Myth ROTJ;
Star Wars the Exhibition has the dent (which is the same backplate as MOM)
ROTJ SE has the dent(which is the same backplate as MOM)
Art of Star Wars ROTJ has a different backplate, but no dent
The skiff barge scene in ROTJ has another backplate that also has no dent;
The Celebration 4 ROTJ pics are very hard to tell because of the gauntlet hose being in the way . The gallery doesn't have any direct pictures of that area either.
As for ESB, very few pictures exist. But I believe there is no dent .
all of the above pictures are from the TDH Gallery.
I'm sure the backplate is clearly seen in the scene where Vader is talking to Lando about altering the deal. If someone would post some screen-caps, that would be very helpful.
The Pre-Pro costumes have very few pictures as well, but you can clearly see there is no dent
The Pre-Pro 1 suit has no dent;
The PRE-Pro 2 suit has no dent;
The Pre-Pro 3 suit has no dent;