You could just buy a new artillery barrel, put your rear sights on it, have it blued, and have yourself a nice Artillery shooter...
One went for $157 on GB a week or so ago...Interestingly, it was sold by Sarco...I have one of their artillery barrels, and they are very nice...
http://www.gunbroker.com/Auction/Vie...Item=206332493
Alternately, you could swap the 4" barrel + sight + toggle (if your toggle does not have the rear sight) for a regular 4" barrel + toggle...I'm sure there is someone here on this forum who has the parts and could perform the swap...