Nedfig, Savage actually made a list of semiauto shotguns patterned after the Browning Auto-5:
Model 720: 1930-1939
Model 726: 1931-1949
Model 740: 1936-1949
Model 745: 1940-1949
Model 755: 1949-1958
Model 775: 1950-1965
Model 750: 1960-1969
I don't know which specific model you're looking at but in excellent condition these models listed about could be worth about $200-$300. I don't believe their is any interchangeability between the Savage 'Auto-5' type shotguns or the Browning A-5 or the Remington Model 11. Hope this helps!
Steve Mace