My Glenfield says GLENFIELD MOD 30A and then next to it Marlin Firearms Co. Newhaven, Conn. on the barrel. If yours is a Glenfield I suspect it should say so on the barrel, maybe not but I think it will. It's still the same gun as a Marlin 336 but just with a cheaper hardwood stock not a walnut one.
Gunstocks, Inc. does sell Marlin replacement stocks.