I'll suggest one other possible maker, Lew Sanderson, although early Herrett's are a good bet too. I have two sets for 2nd model Colt Woodsmans which look very much like this style. Mine may be Herrett's too although I saw a set which appeared exactly like mine sell on eBay for $250 and the seller insisted they were Sanderson. Google Lew Sanderson and you'll find some examples of his work. Regardless of who made them, they are very nice grips.