This would only work is if the bullet was saboted, which means that the bullet would be encased in a thick layer of plastic or light metal peeling away once the bullet exits the barrel.
While this may be what the shows writers may have been thinking of, the description that you provided suggests the shows producers really didn't understand the subject at all.
Since the gas sealing and induced spinning of a rifled round requires the round to engage the rifling, a thin layer of plastic will not serve (it will probably peel off inside the barrel and the normal copper jacket will engage the rifling). The other thing which the show seems to have glossed over is the criminologists (the guys in the full white protective suit who isn't in the show) would be scouring the area and probably discover the pieces of saboting. From there is a short matter to examine the pieces and find the rifling marks.
TL:DR Don't use CSI as a way to find ways to beat the cops.