What those guys said, and a good body shop will ask for trim to fit before final sealer and paint.
There have been horror stories about lost parts, so show up with the stuff needed (like rear window trim), allow fitting, and get it back!

Straight and polished and ready to install is best.

Also, you can take stuff off and restore it as you go.

If you are using repo stuff for soft parts like rubber seals, carpet, tires, and you are SURE you will be able to get them later, it's probably a good idea to wait.