2066 is a low number. 1860's? Strangely crude for an Assmann, but looks very like their 15j model. Cannot imagine that an Assmann made one would not be marked. Lever certainly has the Assmann form, but obviously not the quality. An interesting cheap collectible.
Swiss made some cheap copies. You apparently know what a real one looks like. Photo here of a 19J? Others say it is 20J. Which is right? Dealers seem to have only 20J and 15J to sell for time only movements.