Just upgraded a MEX-LIM-BOG trip tomorrow with km (25,000 km one way). Just curious, for there to be upgradeable space available, would it show up under the "R" fare class, just as any reward ticket space would?

Before calling in to request the upgrade, I checked ExpertFlyer, and it showed J4 D4 I4 R1 for MEX-LIM. One hour after my call, I now see J3 D3 I3 R0.