yea they work...

but why dont you just look at the vehicle you got to look real closely.

1. Notice if any paint is mismatched
2. Notice if any stickers or barcodes are on parts (I found several vehicles like these espically look in the grille for front fascial damage)
3.look at anything and see if anything is bent.
4.look at how the car is sitting sometimes they try to fix it by deflating tires or such.
5.listen how the engine runs and if it smokes or not

hope this helps you