I have not looked into this, but It could be the case of them being designed for Polaris.
The length of the body as well as the extended dimension may not be standard.
And Polaris has a contract with them, this way you have to purchase them through Polaris.
The reason I mention this, I went through this exact same thing on the tilt steering wheel shock.
It was made by Stabilis, the part number could not be located online, and at that time could only be bought through Polaris.
Not saying this is the case, just provided some info.
Edit: Polaris service kit for Tip Out Windshield, Polaris Part# 2207158.
Includes 2 struts, 2 ball mounts and nuts. Approx $65