Except a 515 motor is larger diameter, would cover the area where you see the mounting flange and rivets, it's bolted to the frame from inside the frame, and would likely have "Altec Lansing" lightly engraved on the back of the magnet pot.I'm going to venture a guess and say Hollywood label 515...
How do they sound ????
They are a homebuilt Cabinart knockoff of the Klipsch shorthorn. The actual Cabinart facades do not have that deep bevel cut that this one has, nor do they have the baseboard notch this one has. Great attention to detail!