TPE-LAX and TPE-SFO are codeshares on China Airlines; VN certainly can't fly that route with their current 767s, and I don't think they have FAA clearance to fly passengers to the US yet anyway. I think they may do cargo from time to time though.

The 767s are mixed -- some are 1-class, others 2-class (2-2-1 business class up front.) I believe the one-class is mostly used for shorter hauls and certain domestic flights (I flew on a one-class 767 DAD-SGN the other day.)

VN will however be getting some 777s very soon... is there a chance it might have been the first one of those? Did it have the old blue lettering on white background livery, or the dark blue background with a lotus flower on the tail? (Only one of the 767s has the new livery; all of the 777s will.) I'm curious too... thanks.