I'm guessing you have the Chinese model 2500 Cherokee if it's 2004, that's unless it's the Liberty (not sure if they exported the Liberty as the 2500 was made till 2006).
You might be better off asking a lot of these questions in the Liberty forum as they run the same 3.7L V6. If the engine was overheated till it hit red then you could have charred a little oil in there. A lot of that could be sludge though. When you have the heads off, check the piston walls for scoring and check the oil and coolant jackets for any sludge. If the engine isn't making any weird noises then you might have got off lucky but that could have taken some life off of your crankshaft and camshaft bearings.
[B]1986 Jeep Comanche 126000+ miles[/B]
Long Bed, Chevy 350 TPI (5.7L V8), AX15, NP231
Roll Bar, 15/38.5R16.5 Ground Hawgs, Bastard lift (Custom 3-link long arm system, 4.5" Rusty's front springs w/ 1.75" spacers and 6.5" RC shocks, SOA rear), Dana 60HP/Sterling 10.25, 4.10's, Recessed winch, more mods to come...
[B]1992 Jeep Comanche 174000+ miles[/B]
Short Bed, 4.0L I6 HO, AX15, NP231
In the process of doing a frame up restoration.
[B]1990 Jeep Cherokee XJ 207774 miles[/B]
4.0L I6, AW4, NP231. Tom Woods SYE and Drive Shaft, Rusty's 8.0" Long Arm Suspension Lift, 36/13.5R15 Super Swamper IROK's, Dana 30 Front, Tube Diff Guard, Dana 44 Rear, 4.56 gears, Ox Locker, disc brake conversion