When I add the timecode (#timecode#) overlay during rendering it's in this format: 00:00:00:00

Any way to change it to: 0:00:00

Edit the MLT source code and recompile and install it.

Ok..... Thanks ddennedy.

EDIT: Do you know which file to edit? I just downloaded it and there is a lot of folders and files.

Alright, since you took me seriously, I will take you as such.
src/modules/core/filter_data_show.c
line 101
function frame_to_timecode

Very Useful information , this is both good reading for, have quite a few good key points, and I learn some new stuff from it too, thanks for sharing your information.
keyword tool