I am an amateur collector old kaleidoscopes. I am not an expert on this and would really appreciate some input from experts if this kaleidoscope is from the Victorian era. How could I tell? What questions would distinguish between a Victorian era kaleidoscope and a more modern kaleidoscope?
According to this site on Antique and Modern Kaleidoscopes there is a significant time period, about 1900 to 1980, when kaleidoscope production was almost universally of paper-covered toys. Both prior to and subsequent to that time period, quality kaleidoscopes are produced and sold as artworks. The wooden lens mount, sewn cover (apparently woven not silk-screened) and antique look would seem strong evidence that the item is actually the antique it is claimed to be.
Unfortunately, since kaleidoscopes are usually made from brass and wood, the materials alone will be difficult to provide a dating.
Normally a dealer will learn stylistically what is typical for each time period. Using style recognition, however, is not proof against forgery or a reproduction.
I would recommend looking very closely at the metal working in the kaleidoscope, especially the fittings (screws if there are any). In Victorian times it was much more common to use files. In modern times we tend to use grinders. So, if you find file marks on the metal, it is sign of an antique. A related sign is the use of emery. Nowadays, emery is rarely used as an abrasive, but it was universally used in Victorian times, so if you learn the difference between emery scratches and aluminum oxide or carbide scratches, that can be a tell-tale.
The fittings are also a giveaway. Since about WWI, all screws have been standardized and brads are made to machine standards. In Victorian times, screws were irregular and there were many different types. Also, things like brads were often handmade or made by one-off machines to no particular standard.