Sadly, recent sales results show that correct details are not that important to final price. At least not at the moment. Many of the cars I have tracked at auction have a long list of minor and major departures from original and still bring top dollar. I know there will always be a segment of the buying public that keys in on original details, but most buyers just want to know that the car was originally a factory specific model and then just look at the quality of the work they see without asking if the materials are correct for the car or even the year. This may change in the future, or it may get worse. There is no way to tell.
The bottom line is, if original details are important to you, spend a lot of time, do a lot of home work and ask a lot of questions before you buy. Otherwise, you will feel pretty bad when you bring your new aquisition to a meet, only to hear form the experts why it is not correct.
If those details are not important to you, you should still make sure the car you are buying is actually the model being represented and that the work that looks so good today will hold up over time. Otherwise you stand to lose a lot of money.