Glass is the same for either left or right. Rubber would be next to impossible to find. I think you best option is to buy a used mirror. I have two for sale. One has a scratches, including the glass, but it's all complete and I will let it go for $38 shipped. The other one is in better condition and I will take $65 for it. Let me know if you are interested and I will send you pictures. Best way to get in touch i p.panchev at gmail dot com.
Cheers,
Pete