Dan I don't know what happened in 1896 but I do have listed guns that have 1896 stamped on the side plates starting at 51936 (1896) and going to 52784 (1896). Not sure when it started or stopped but it was 1896. I also have that serial number from you stating it does have steel barrels (2016).

I have your 5548X listed in my records as well as 5790X a 16 ga. but do not have 573XX.
If you could email me at jdavidw1@comcast.net and give me the full information I would appreciate it.