Well, I've tried Uberti's web page and Cimarron's web page and can find no mention of pinched frame models. Uberti calls theirs Old Model and New Model, and Cimarron calls theirs Blackpowder and Pre War Models. Some photos show a knurled head base pin retaining screw, others a slotted head screw.
I've never seen a pinched frame, not that they don't exist. As pointed out mine was a Flat Top, so of course, no pinched frame. I'm finding that variations exist in Ubertis according to the importer. My three are two from Stoeger and one Cimarron. My only other one was from Iver Johnson, and that ca. 1975.