No they're not Mosin variants. The Schmidt-Rubin is a Swissicon straight-pull bolt action rifle. They're known for their excellent quality and are typically very accurate and reliable.

If you're absolutely set on a Mosin Nagant, I'd save up a little extra and look for a Finnishicon Mosin or an early Hex receiver Russianicon Mosin. The $90 arsenal refurb ones are not really worth it in my opinion.