Antique desk (?)

Purchased recently in the Chicago area. Appears to be old, but also appears that two main drawers were rebuilt at some point (with new sides and bottoms) by someone who really knew what they were doing. Interesting little thing - fits well in the room where it was intended. Replaced screws on the underside (which hold the leg assembly) with lag bolts and washers, which makes it much more stable. Took the stain pen to it, which cleaned up any scratches or nicks it had, attached heavy felt pads to the bottom of the leg assembly, and then gave it a good cleaning and oiling. The top box with the little drawers and "cubbies" comes off completely. Would love to know more about this desk, its style and its age, if anyone has any info !