The originals were plastic (probably nylon). I just changed out the originals on my driver side door. The originals lasted most of it's 39 years and 178,000 I have run my '68. They only got bad in the past few years. The passenger side originals are still fine. If it's like most of the repro stuff, I doubt the new ones are as robust as the originals. (Although the nylon coating on the factory timing gear, to make it quieter, was not the best idea. )