My 73 Dodge D200 has a master cylinder I might need to replace as I cant find a gasket for the lid. The port for the front brakes has a TEE for the brake line going to the trailer brakes that have been installed in the truck

Question I have is,if and when I do replace the master cylinder,will this tee play any part in bleeding the brakes once the master is installed?

Is there a difference in how brakes are bled when trailer brakes are installed?