its an interesting concept. i am sure i have never seen kanji used on a clock before.
sometimes the original or archaic kanji are used on elevator buttons for example, but i have never seen them on a clock face. possibly something to do with the difference in the way numerals and kanji are employed when expressing time.
the words 'hours' and 'minutes' are always added when saying the time so you dont say 4:25 (four twenty-five) but "four hours, twenty five minutes".
for those interested, the simplified modern kaji are on the left, and their archaic counterparts on the right.
一 壱
二 弐
三 参
四 肆
五 伍
六 陸
七 柒
八 捌
九 玖
十 拾