Re: 5.7 hemi engines
Easy from the outside unless its an 08.
05-06 have the black plastic (thick as in tall) cladding along the sides. 07 has thin. The 05-06 have the separate rear tails (ie. turn signal and brake light/tail light). 07+ has combo (one bulb).
08+ has the new front end and 6 spoke wheels on all models. Also different shift knob, soft touch interior and dash has white lcd and backlighting vs green on 05-07.
now for the export wk the tails may not be noticeably different but you should be able to narrow it down just from the visual cues on the front end (05-07 vs 08+). as far as the 08 model can't help you there, but I am sure someone will be able to tell you.