Yes, either way works, as long as you don't add any modern electrical stuff, like a radio or do an alternator conversion. With positive ground, you have to be careful that some unanointed individual doesn't try to jump-start it by hooking up the cables as if it were negative ground.
My suggestion: as soon as you contemplate adding a radio or some such thing, switch to negative ground. Although some such components are available in positive-ground form, many are not, and eventually you may have to convert. You don't want to buy, say, a positive-ground radio, then have to replace it later when you do the conversion.
The only real advantage to positive ground is that it's original. If that's important, fine; if not, I'd suggest converting it. You probably will, eventually.