It's definitely 'malleable iron' and not steel.
Even Smith & Wesson didn't 'harden' their products until 1914, so it's not in the minority...
Meriden made firearms for 'the Trade' and they made a helluva lot of them - tey were of 'good enough' quality, but still, when your primary interest is in buying by price point, you can imagine that they weren't top-of-the-line when brand new...
So long as you're using a BP load - or a 'standard' load - the weapon should hold up enough for your purposes, and since these were produced well after 1899, smokeless was definitely available.
They were meant to be carried a lot, and shot little...
Good Luck!
Vaya,
Scouts Out!