positive ground on 49's ???

[tonkadawg]

I finally got some time to look closely at the wiring on my 49 and noticed that the positive terminal of the battery is grounded to a frame rail. The negative terminal wires directly to the starter - truck is still 6v. All the wiring diagrams I've seen for this year say the truck should be a negative ground.

Anyone have any ideas of what's going on?

Can I safely swap the wires on the terminals and not do any damage to the truck?

Thanks,

Matt