A ball lock QD sporting a 1/4" MFL thread usually has a captive gasket at the tip. Whether a PTC connector or a standard swivel, no additional gasket or tape required.
That said, you can use the same PTC connector on a bare 1/4" MFL thread (eg: a 1/4" MFL bulkhead) as the connector itself will deform to seal directly to the metal male side with sufficient torque.
fwiw, the only PTC fittings I used with captive gaskets were for the faucet shanks and my flow meters...
Cheers!
That said, you can use the same PTC connector on a bare 1/4" MFL thread (eg: a 1/4" MFL bulkhead) as the connector itself will deform to seal directly to the metal male side with sufficient torque.
fwiw, the only PTC fittings I used with captive gaskets were for the faucet shanks and my flow meters...
Cheers!