I'm flying DFW-MEX soon, and I had a schedule change. I'm now booked on a 319 instead of a 738. I know DFW-MEX is a short flight, but I'd like to get upgraded anyway. As an EXP, I've never cleared a single upgrade on a 319. Is there any reason to believe that this flight down to MEX would be any different, or is this considered an "easier" upgrade.

I may call and change to an earlier flight on a 738.