Agree of letting this run its course. However if your friend is making these commercially, chances are he has those gigantic machines and presses. Seen those before... it is disturbing mate believe me. Our problem is min. qty to for him to break even (you can't say NO to a friend!). We'll need to buy min 500pcs of this small seal just so he can at least cover the cost of the energy required for heating his machine's rollers (used to melt the rubber). Molds cost are not included yet... those can go up nasty as well even if they are made of aluminum.
RE material; they will be most likely made of EPDM rubber. Or request for them to be (please
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The alternative:
Someone (Charles, you there?) to buy the casting kit and do them at home. Perfect for a small qty run. Doesn't require much to get this done in less than 48hrs (for someone that never done casting before). You just need a pint of casting silicon + catalyst and some modeling clay (plasticine?) to do a two-parts mold. Tutorials all over Youtube (I've just checked).
The rubber is also sold by the same sellers selling those DIY casting kits. They come in a liquid form with curing time ranging from 6 ~16hrs. Silicon rubber being one of the best and most used although not the cheapest. You can colour this stuff using plain dyes (black, gray, red, pink, whatever). Very high heat resistant... not sure about discoloration under UV however (might turn white, but after ten years).
Molding/Casting/Replicating a part is as easy as making a chocolate cake in all honesty. Today you can find resins in liquid form of any sort (silicon based, rubber, epoxies, acrylics, plastics, what else....)
Youtube "casting two part mold" type search. I've done a lot of that in the past (custom gaskets, o-rings, little plastic gears, anything really). Very fun and relaxing hobby