The 1885 portion of my house's windows are outfitted with the most unique window locks I have ever seen (and, indeed, I have never seen them elsewhere). Please see attached photos. The unlocked position is when the lever is in the vertical position. To lock the sashes together, you simply pull the lever down and towards you, joining the two parts together. The idea is simple, however, in practice, they work poorly. The sashes must meet perfectly both horizontally and vertically for the lock to operate, and, like most old house windows, most of mine don't.
The design on the lock appears to be "broken leaf" although I am aware that that idea was copied through many different hardware manufacturers. The mortise lock hardware in the 1885 portion of my house is Chicago Niles (very unique), so the window lock might be made by that company. That would explain its scarcity.
Has anyone out there seen this specific window lock before? Does anyone have any extras to sell or trade? I am missing roughly four complete locks for my windows. Thanks for everyone's feedback and comments.