Does seem to be a discontinuity, dunnnit? I choose for the moment to resolve it by assuming Faye and Marten meant fully ... functional ... humaniform AnPCs.
If you mean in the Lt. Cmdr. Data sense, BoyfriendBot's "functionality" was "a feature to be implemented at a later date" per #1011.
SalesLadyBot is yes, bigger, than Pintsize but it looks like she has a fixed mouth, certainly less fixed than Pintsize's.
Marten's reaction to BoyfriendBot was more muted than Faye's... a careful reading of his lines from that arc doesn't necessarily exclude his having interacted with something like SalesLadyBot. I think BoyfriendBot's innovations over SalesLadyBot's are in the skin and articulability(?) of the mouth (shown when Winslow inhabits him).
Surely a humanoid robot that has at least human-level balance, walking speed and arm/hand articulation is more of a challenge than a moving mouth as Pintsize has. I mean, BFB doesn't even have a properly human-like face, so that's well into the realms of present-day animatronics.
i.e., BFB is basically SLB's body (in male form) + Pintsize's face. And yet is a bleeding-edge prototype two+ years later.
"BoyfriendBot" appears also in 1997. So add that to the wild mass guessing.
Well, if he was JEC's "latest prototype" in #1010, being on-sale some time later - especially given the advances to Momo II-level - that works well enough since QCtime has accelerated a lot since the early days, where the first 1000 strips took something like two months.