Good luck finding a Rickenbacker truss rod cover. Rickenbacker keeps as tight control on those as Alembic does on logos. I just picked up a 1987 330 that sustained fire damage. Rickenbacker won't sell me a replacement for the truss rod cover that partially melted unless I send them the damaged one first. You can find Rickenbacker TRCs on eBay, but they run $200-$250!
Bill, tgo