That is the same tail light used on my 2007 Winnebago View. It was made in India. The socket is plastic and chrome plated to be a reflector. I had lots of troubles with the contacts. The bulbs are 1157 bulbs and yes, polishing the contacts carefully, bending the ground contact strip on the side of the hole where the bulb fits (socket is hard brittle plastic, remember) and adding solder to the bulb contacts helps. There is no replacing the socket, as it is the entire light assembly (sans the lens) and it is no longer made.
Good luck
Charles