My s58 one was made by Cj marine. I don’t. Know if they were the oem but mine was sufficiently old and knackered I assumed they were.
Mine was £660.
They are supplied with self fit poppers as they don’t know the exact location of the studs on your boat.
Given I was single handed and the thing is large is took several hours to fit - so my top tip would be get a mate along and see if you can borrow a tool that puts on the push studs as the hammer against a hollowed our dish means removing the thing 20 times during fitment !