Original globe in serts for an 1885 high wall|Winchester Sights|Forum|Winchester Collector

I am trying to find a couple of the original square style sight inserts for my 1885 Winchester front globe sight. I have the round hole type that came with the rifle but perhaps would like to try a post or another style. Tons of other manufactures of inserts out there but not these Winchester ones. Any clue where to look. I know the Montana Arms has some but they are thinner. I would like to keep to original equipment if possible.