
Here’s another example, spotted on eBay. The first date listed, April 1, 1899, is not possible for a US patent because that’s a Saturday. They probably meant April 11, 1899 which would be for patent 622,753 for a screw-door safe.
Then there’s August 12, 1904 which was a Friday. All US patents are issued on Tuesdays.
I suppose these could be foreign patents but the first one sure looks like a typo. I would have expected a plate like this to be semi-mass-produced and thus scrutinized a little more carefully before production, compared to one-at-a-time hand lettering.