Reseacher and Skeettx,
The gun in question has really nice upgraded wood with a grip cap so I am assuming it is a Model 430.

The owner said the gun has 37 and 6666 on the bottom of the frame but no other numbers anywhere else on his gun. Also there are no markings on the barrels to indicate the model and the company that made it. Did the early 420's and 430's have serial numbers?

Just curious, but did Stevens/Savage make the 420 and 430 with a malleable iron frame like Marlin did on their model 90's? Also, were the 20ga. and 16 ga. 420's and 430's made on smaller frames like the Model 90's?