If you put numbers on the skin, it will just be numbers over the skin. Unless you take the actual tactical number out of the skin, separate the paint and weathering into separate images and then submit the skin, the results would be pretty bad.
(this is the only uncompressed semi-complete skin I had, mottling's terrible I just started on it

Should have 117 kills on the rudder as well... )

If I over weathered my skins like most skinners do, it would be obvious that the 13 is completely unweathered, unlike the rest of the aircraft, as well.
Nose art is the same way, but it's small enough that it's not totally hideous, unlike tactical numbers.