So far you have narrowed it down to some choices.
OEM Rubi 03-06
OEM Rubi backing plates with Explorer bits, caliper, rotor, pads.
ZJ backing plates with Rubi bits.
ZJ backing plates with Explorer bits.
Stop Tech conversion with some bits.
ECGS conversion with some bits.
Tera conversion with some bits.
To narrow it further, you need to see what pistons are in the calipers. Steel piston = 8.8 caliper. Phenolic piston = ZJ, Rubi, and Liberty Caliper.
Pad shape may help to figure out if it is OEM Rubi or ZJ since the little anti rattle clip can be on either or neither.