I understand this plastic piece covers two slots that allow you to see a frame engraved VIN. This piece was off when I bought my 21 Prime. I clicked it back in place, although it fits quite poorly. Question is: Are the covered slots open to the outside of the car? Can moisture get in from under the plastic cover?
No. The slots for securing the cover are in the front floor cross member RH, which is separate from (but attached to) the floor pan. The slots are open only to the void between the cross member and the floor pan. See catalog Figure 58-01, Floor Pan & Lower Back Panel; on that page, click the third image, which shows the cross member, at upper left, with part name code 57451A.
