Springfield armory Range officer for Bullseye

Im looking to purchase a Springfield armory Range officer for Bullseye competition and would like opinions as to the best model to start with. 

I would like one with a rail so that does narrow it down. The few I’m looking at are The Range officer operator P19131LP, Range officer operator elite P19131E, 1911  Loaded Lightweight Operator PX9116L18 .

I would also like to know if there are any advantages or disadvantages to the 1911 Loaded’s aluminum 
Alloy frame other than the seven ounces over the forged steel frame of the standard RO.

Thanks in advance.

I like the heaver frame for bullseye shooting and the rail has more meat to drill and tap for frame mount red dot I did a MC operator it works good

Had me going, since the first two had the wrong model number.  They start with PI, not P1.  All of those models have a rear sight that is not something we look for in a Bullseye pistol.  If you are going to immediately remove it and convert the pistol for a red dot of some sort, no problem.  If not, you should look at the Range Officer with the Bo-Mar type rear sight: PI9128LP.

I'm probably going to put a red dot on the slide. So I guess I'm better off with the slightly heavier frame. Thank you for the responses