OT: Question about auto electrical test device

[mcgarrett]

A friend gifted me with a vintage Heathkit auto analyzer unit. It's in very nice shape and has all the test leads and accessories that came with it along with the instruction manual. My question is, can I use this tester for my 6 volt positive ground vehicles? I would appreciate some guidance from our more electrically gifted colleagues here on The Barn.
(I posted this on the Model A Forum and thought I'd post it here as well.)