I put a set on mine.... I just can't remember who they were made by.... seems like williams or Millet .... maybe I can figure it out...
I'm pretty sure they were Williams FireSights.... you can go to their web sight but it is kind of hard to find.... go to firesights for pistols and you should be able to find a listing of them starting with Browning buckmarks... and about the the fourth choice down is for the MKII and MKIII Bull Barrel, Item number #70957.
Have used Williams Firesights on several of mine, including some on some 10/22's and have been very pleased with them. Williams also makes a real fine peep sight for the 10/22. Try 'em, you'll like 'em!!
cmacrph