Found this article I had stashed here on Fred somewhere. Finally found it for you. Not written by me, just ccp to here.
Older Brownings are marked by choke by using a symbol or symbols on the left rear of the barrel.
Full: *
Imp Mod: *-
Mod: **
Imp Cyl: **-
Skeet: **$
Cyl: ***
And remember- Any choke marking is a rough guide. When you pattern your barrel with the shell you plan to use, it might be tighter, looser, or perhaps even right.
From my limited experience, older barrels pattern tighter than they are marked. The theory is that shells we use now with the plastic cushioned wadcups protect the shot better than the old shells that might just have some fiber or felt wads with the shot poured on top. The better the shot condition when it leaves the barrel, the better the pattern.
I imagine those older barrels' choke markings are a lot closer match to the shells from 50 years ago.