There is a place down on west Colfax that does it, MJ Tulo.
Can't speak for his work but I believe he is the only local source.
720-921-5126
Monday - Friday, 9:00AM - 6:00PM Mountain Time
Saturday, 10:00AM - 4:00PM Mountain Time
By Post

MJ Tulo Gunmakers
9797 W Colfax Ave, Ste 3Vv
Lakewood, Co 80215 USA