The number usually refers to the size although if I remember correctly there was no uniform standard such that a 3 from any manufacturer was always identical in size.
Here are two links I had for crotal bells. https://classicbells.com/info/bellMakers.html http://www.ukdfd.co.uk/pages/crotal-bells.html#Anchor-Th-55036
Yours is late 1800's which is seen by the metal..shape and the petals only being on the lower half..IIRC.
Some may have a makers mark but while I have found quite a few over the past few decades...I never have found one with a mark.
Hey did you ever end up finding any more good ID sites for bells?
I just snagged one last night and I was pretty surprised to see some initials and markings on it. I see the letters WFB, and a horse??
I haven't had any luck finding positive id on it yet . But I had seen somewhere in the yahoo searches some crotal bells had the words wells fargo in some of the search results??