I would have to say that 98% of the package trays come out of REM located in REM. The texture is not as pronounced as the originals. They are not perfect, but are better than a rotten or broken one. If that is a concern, then your going to have find a good used one which can be painted to black or the desired color.
The worst part about ordering the package trays is that shipping is going to cost as much as the part. Due to the oversize nature of the part, it goes as "Oversize" in the shipping department. If your attending the Indy Cylinder Head show in March, we can bring one to that show for you to look at.
Correct Mopar weatherstripping is our specialty, but we stock and supply a wide assortment for all of your restoration needs.