I have occasionally seen cases where a time like 12:47 am is referred to as 00:47 am, with the colon, and on a clock that is otherwise using 12-hour clock conventions.
I can’t remember specifically where I’ve seen it, it might be on Japanese TV. I live in the US.
Is this a common thing in some other countries? I don’t think I’ve seen it here, but again, it’s just something I have noticed in passing and was curious about. Frankly, it seems like a good idea to me.