I saw a 27 laser 1997 with 454 and a bravo III, was a bravo III
a stock drive option for this boat, because I have never seen one with this combination , when was the bravo III introduced

Yes, you could order a Bravo III on a PQ. I know of two 1998 270's that were sold at the local PQ dealer with 454 MAG's and Bravo III drives. The Bravo III came out around '94. If you don't mind giving up a couple MPH on the top end, where most people spend a small majority of their run-time hours, the Bravo III will give you better manners around the dock, quicker time to plane, and more efficient cruising. If you are looking for every last MPH, then you'd want to swap the lower or the entire drive out for a Bravo I.