Yes, there are such Jettons, for example, jUSDT (USDT transferred from Ethereum via bridge.ton.org) has the decimal precision set to 6: https://tonscan.org/jetton/EQBynBO23ywHy_CgarY9NK9FTz0yDsG82PtcbSTQgGoXwiuA

But it's also easy to create such a Jetton yourself using https://minter.ton.org. One just has to specify the decimal precision in the corresponding field on the website. By default it is set to 9, and it seems most people just don't change that number.