Yes, it should make a difference. I've flowen SFO-IAD-EZE 4 times in F in the last few months and my bags always come off quickly in EZE (with F priority tags).
Baggage handling in EZE is very fast and efficient (and the baggage claim area is close to the gate where you will deplane).

I've often made it off the aircraft and through immigration in under 10 minutes, and never had to wait more than 10 minutes for my bags. You will have to have all you bags X-rayed at customs before you can leave the secure area.

John