M17/P14 Rear sights

Gday everyone,
starting to dwelve into the world of the M17/P14 family. Much to learn but one that I would like to know is how many variations of rear sight did they use in service and aftermarket. I have viewed the one on the No3 Mk1 sniper rifle pictorial. Also seen one that was used on a rifle for highpower shooting.Similar in appearance to the P14 one but also very similar to the Nk1 sight for the No4.
Any stories and or pics would be graetly appreciated. I also have a view to buy one of these and also the PH 5B for th erifle.
Many thanks in anticipation fellas
Ned:beerchug::beerchug::beerchug: