Sorry to necro this thread, but I just read this comment. Are you sure? I found one of these Acer keyboards for a decent price, but if they're not PBT afterall then it's not really worth it. Anyone else?
Apparently some are PBT and some are not, probably depending on the exact model.
I have seen differences in the case: wedge-shaped vs. reverse curve, and that the Sys Rq and Break legends are front-printed on some keyboards and top-printed on others.
My keyboard with ABS keycaps have the wedge case and front-printed legends, just as the keyboard in the auction in the first post.
There are picture of PBT keycaps on
Deskthority, but those keyboards have reverse-curve cases and top-printed legends.
I would wager that if the keyboard has reverse-curve case and top-printed legends then it is more likely that the keycaps are PBT.
However, I still haven't seen any keyboards with Acer-switches where the stabilisers are compatible with either Alps or "Costar"-stabilisers.