Well, my "read" is still syncing from the phone to gmail. But now if I read it on the PC, it's not syncing with the phone...even after a message is sent. Maybe it just needs time.
***EDIT***
Yep, just needed time. After an hour or two...or maybe longer, the BB will catch up with the Gmail inbox read/delete. It seems that it takes time and another message sent to gmail to push that through.