That is a nice second generation unit lock. That was a hotel lock as it is non dead latching lock but the thumb turn blocks the latch. By the date on the dust cover I would agree with a date of 1900-02 as there was a few more patent dates on newer ones. I have a few of those in my collection. When you get time I would love pics of the inside and outside of the trim plates. Thank you for posting pictures of this one, I hadn’t seen that trim design in catalogs before and it is a very nice one.
The locks I was trying to find are like those pictured above in the catalog cut but the two without the outer knob and maybe nothing on the inside. I have seen one on ebay but it was sold at a higher price than I could afford at that time. If anyone had the cabinet lock one pictured I would love pictures of that too.
Just so you know the model number is stamped on the inside of the escutcheon plate.
