Of course you can swap the circuit sheet. It will work just fine. Careful at the harness connection where double sided tape holds the sheet to the light. On the passenger side, also be careful when inserting the white bulb socket into that housing. It will go but it needs to be coaxed in, since the slots and keys on the socket are slightly different. Any one who tells you you can't use a pre-85 light housing and have full function lights, including third brake light circuit, hasn't tried hard enough.