$1.0000 = $1
I've seen this error a few times around here.
A . is a decimal point.
A , can be used to make big numbers easier.
if we consider the anglo-saxon numerical codification, you are right. I come from a latin European country, and our standard codification for numbers is the comma (,) for decimals and the point (.) for thousands, millions, etc. so that's why I'm actually wrong in an international environment.
By the way I'm pretty sure that, according to the International System and in the accademical world, we should use the point for decimals, and don't use anything for thousands, millions etc., so to be completely right we should write 1000 if we mean a thousand