That's wrong for either method of decimal/separator mark. None of them omit zeroes without otherwise notating quantity, e.g., 12,8K or 12.8K for twelve thousand eight hundred. Here's an article about it.

https://en.wikipedia.org/wiki/Decimal_separator

Most countries that use periods as thousands separators and commas as decimal marks use the metric system, hence my teasing them.

Edit: not to add, by your logic my response, 12,8KG, would have been correct anyhow. Are you taking the piss?