I can supply good photos of some originals, and can supply some measurements of one or two that I have.  AFAIK no one has ever reproduced the P-M spirit level wind gauge front sights in any quantity.  The original sight supposedly was imported from Britain (?), and is similar to those used on some of the Rigby and other long range Brit muzzleloaders.

fazer
  i have seen for years many peabody martini's without front sights.i tried for several years to get some made,even tried to myself but a couple of years ago i was finally able to get several made by a master machinist.i still have a few left. they were not cheap to get done but they are exact replica's.i don't seem to have any luck posting pictures here.if you will send me your email i will get you some pictures.they were made with an extra aperture also.the man that made them said he would never never ever never make any more they were the hardest thing he has done.i get 1100.00 each shipped.i am not making but a few bucks each,i needed several myself and have sold half of what i had made within a week of getting them.i have never listed them for sale just word of mouth,but i want to see these old guns with original equipment not repop junk.they also have the spirit level and providence tool company logo on the front of the base.
                   tony <><