My 1941 Super has a slight ring, as I do my own repairs I would fill the crack with low melting point silver solder (lead free).
I have a 1925 Besson trumpet awaiting restoration with a much bigger crack in the bell extending into the flare which I will repair with a higher melting point silver solder. The Besson Bell rings when flicked, it does not have the tone ring.
I am not a trained brass technician, a working lifetime in electronic and electrical instrument making and repair.
My feelings are to keep the horn, they are great instruments.
Regards, Stuart.