Greg,
I just received my member guide from AAdvantage yesterday. In it under the TWA awards are a awards for First Class/Business Class Ticket and an Award for a Premium Class Ticket.
With this in mind I think you may well see PW 767-300s converted to 3 class service. With regards to the original question regarding Hawaii, I think that since TWA has so few 767-300s you'll likely see them all in the same configuration. I would guess that probably means 3 class service in order to support the CDG, LGW & CAI flights.
JMHO...I may well wind up being wrong.