the metal casing on the pass side behind dash ( i presume you mean of the ecu) should should have a sticker on the bottom saying ofab or ofac, this is used to denote which ecu you have for parts,chips,etc. if the sticker has gone from there, you can remove the ecu & find another at the top where the loom plugs in. or if you know what a 4x4 saph coss map sensor looks like (triangular), & yours is the same, you have ofab, (best one)