Just browsing around on a certain free ad website and found what looks to be a nice US civil war musket called a Springfield Zouave. I am familiar with Springfield but never heard of a Zouave musket before so I decided to look them up and found out about their history ect but my question is, the one of said free ad site has a V sight similar to the Indian P53 muskets whilst all the other Zouave muskets I have found had adjustable rear sights, cannot find another that is exactly like the one for sale. Were there varying types of sights for these muskets?

I know next to nothing about American Civil war muskets and was hoping someone could fill in the blanks for me.

Cheers