Guys, looking at a 78 J-bass. Guy tells me it has been refinished in a Sienna Burst. I kinda like the color because it is a little unique. He also claims he installed Dimarzio pickups, but the originals will be included. Anything I should look out for on this? The nut looks brass so I would imagine that was changed. One question I have - What is the screw in the middle of the pick guard for? It's right between the neck and the neck pickup. Was this common? Anything else out of order you see please point it out. Truss rod looks like it comes out at the headstock - is that correct for a 78? Thanks!!