Nah, I've never seen any templates or measurements for that.

If it's a tight fitting top like my Surplus City top then you'll probably want to get as close to original locations as you can instead of laying the top on it and best guessing it.

Did they leave the holes from the screws holding the snaps? If they covered with bondo or paint you might be able to sand it down and see them.

On my next day off... could be a little bit... I can pull my top and do some measuring.