I installed a gen 3 connector and that is not an optional part. Anyone who has a gen 3 connector will have to use it to install theirs. Earlier versions had an optional extension that could go behind the connector but the gen 3 does not.
Your best bet is probably to contact Tesla and see if you can get it straight from them. I think the bulk of the connector price is in the electronics and cable that is in the front part so it should be way less than half the price of the whole thing.
Or wait for someone to sell parts from one that fried their electronics or had a bad cable.
Either way, you're better off posting in either the Charging Infrastructure (
Supercharging & Charging Infrastructure) or Marketplace (
Marketplace | Tesla Motors Club) sections rather than an individual model section.