Fisher also produced some unmarked Blacker anvils it seems. Those would be later ones, similar to later unmarked London pattern Fishers. Guessing mid-1940s timeframe
Not saying the anvil here in question here is a Soderfors, but Soderfors are some of the best makes of anvils out there and many of them meet your description you mentioned.
Highly doubtful that one company bought a huge number of Soderfors anvils, over many years, to have them stamped similarly like this with numbers as we find them now. And with number stamps that are of a Swedish looking character font.
Correct, that's an old style stamp. Sometimes you see numbers like that sporadically, could very well be a serial number. or steel batch number. But they were not serialized like American manufacturers through their entire production history.
While Soderfors didn't have serial numbers, a month stamp would at least give them an indication of production timeframes after the fact if there ever was a problem with a certain batch of steel or raw iron ore.
I've had a theory for a few years now, after examining and collecting thousands of anvils stamp pictures.
With Soderfors I kept seeing numbers below the year. I started keeping track of those numbers, and which ones appeared. They were always one through twelve, never higher than thirteen. I still have never seen one higher than 13. I believe the number being placed that close to the year stamp, and always being 1 through 12, this was the month stamp of the associated year.
Yes, they are common like that.
The I.I.& B. Co, then into Vulcan, and even Badgers, all had these type of feet and raised numbers at times.
Vulcan bought out Badger, so there was a mish-mosh of patterns over time, can't distinguish which is which.
AIA indicates 1911 for the serial number shown.
You can see where the ACME stamped was whacked right on top of the Trenton diamond logo. This was fairly common for Trenton Acme's.
I'm wondering if this may have been a repaired anvil by Trenton. Is it possible to get a better picture of the base underside without such a drastic angle?
Trenton had some variations in their cast bases aside from the two that are normally seen.
Like looking straight on/down?