I just got a 2003 Silverado and note there is no compass in the rear view mirror and I have freinds with them. The mirror has a power cord run to it and appears to be identical to plugs the compass mirror has on my friends Chevy. Can I just go to salvage yard and obtain a compass mirror and do a swap out or is there other issues to be considered? My gut feeling is the same wiring harness is in all the Silverados as it would make sense from a engineering and assembly standpoint on the line. Hopefully someone can give a definitive answer on this as I would love a compass mirror. Is there more than one variation of these?