Today, some clocks with Roman numerals have IIII and some have IV. This goes back to the Middle Ages, which invented the mechanical clock face. The Durham Cathedral clock, which dates from around 1500, uses IIII; the famous Prague orloj from ca 1410 uses IV.

So-called "subtractive" numerals (IV) were not that common in the Middle Ages. It's much more frequent in texts to see "viiii" or "viiij" than "ix", and so forth. In a post in this earlier thread, I give some medieval examples of additive notation.