if you want ones that are correct, heavy with the cording in them, you have to make them yourself.
The rubber is available... from restoration supply.
James, I'm sure that is totally correct in that I purchased the material from Restoration Supply at Carlisle event in anticipation of making my own but never used that material. Reason, ordered set from Heartbeat to someone who was advertising correct thickness and bingo, they had the thickness and stringer look. Someone on here several years ago (noyenko I believe) used the same a-arm flaps and lightly sanded them to show the stringers as originals. I did not do any sanding as noyenko but spent more than a day making staples and installing with the same look as originally installed. And for anyone trying that it takes two people IMHO.
Joe, yes, restoration supply is a company based in PA.
Tim, if you want material I still have the sheet and will send you what you need for just the cost to ship! My gift down under! LOL