I gave the theme a look, and there seems to be a problem indeed. The author mentions that the 06-Tiny font is needed, but then he doesn't load it, and of course he doesn't use it. That's the font that seems to be right for the clock (I tried it and it works), but the problem is that he uses three fonts, and using the right font for the clock implies correcting the fonts used in other places (viewports), which... I'm not really willing to do, sorry

He also loads the same font twice with different number identifiers, so fonts 1 and 2 are the same.
Fixing this would need to replace, on every pertinent viewport of every screen (wps, fms, sbs), font #2 with font #1 (or leave the font parameter empty), and then replacing font #2 loading with 06-Tiny.fnt (instead of the current 14-Rockbox-Mix.fnt), then specifying font #2 for the clock viewport (of course all that would have to be tested, there could be something else)
The funny thing is that no one said anything before and the theme is pretty well rated, so it looks like you must be wrong for not liking it as it is now

Edit:
A quick (but maybe not so pretty) fix:
Put this line (wps, fms, sbs files)
%Fl(4,06-Tiny.fnt,11)
after
%Fl(3,08-Namil.fnt,11)
and replace
%V(-25,10,25,7,1)
%ar%cl:%cM
with
%V(-25,10,25,7,4)
%ar%cl:%cM