A friend on mine's car (95 Lumina) got broken into, and the replacement dash only came in grey, so it had to be painted to match (black). The body shop did all the repair and paint. But the paint is scratching off way too easily. Should this happen? I believe it's happen on the plastic parts as well as the vinyl parts.

This means you have an adhesion problem....take it back to the bodyshop and have them re-paint it or get your money back.

Usually this will happen cuz the panel was not preped correctly.

they probably didn't let it dry long enough before they gave it back to you. Also if they didnt prep it properly the paint wont stick

its b/c they never washed the dash and parts they painted. if they didnt let it dry, it will dry sometime so thats not really a problem. but not washing it down with dish soap or stuff that cuts the grease, it will not stick. armorall, car shin stuff will not let it stick

Maybe I wasn't clear, but it was a brand new dash.

go to your local auto superstore or whatever and pick up a bottle of vinyl dye in black, it works really really good.