This may be old news. However I thought I would mention it for those who are not aware. I have an older Colt Hbar (1994), which has seen a lot of use, and many dings.  Just for grins I ordered some Birchwood and Casey Aluma Black  to touch up the dings. Nearly all of the scratches and dings cleaned up to a near perfect color match, and most are not visible. The deeper scrapes matched up in color, but are still visible due to their depth. Kind of adds character.  I am very impressed with the results.
MB

You might find the alumablack is not very durable.  We learned the hard way.

What happened?
MB