I am one of maybe a few who is a Ted Williams 300 groupie. They are great shotguns ! They were in fact much better in my opinion than the Winchester 1400 from which they are kin to. They had better wood, better balance, double beeded sights, vent ribs , and a vari-choke . And everyone I have seen with the exception of a few were in excellent condition. There is no data or production dates available . I own many and the differences are subtle the ones made between 1964 and 1968 had chrome triggers, and a thicker pistol grip, the serial numbers were under the reciever, the ones made from 1969 on had the letter Q in front of the serial numbers the earliest one with a Q serial number to date I have found is Q29832, another change is the pistol grip is much narrower, and the trigger is now matte black, another later change for the 300 is that the serial number went on the left side of the reciever the earliest number I have found is Q57599. The highest serial number I have seen is Q139463 probably near the end of the Ted Williams production run which ended in 1978. I have been trying to figure production dates by checking gun auctions and gathering barrel codes and serial numbers and original owner info on the 200 and 300 Ted Williams. Thier does seem to be some barrel code date sequence but I have not yet been able to figure it out. But yes the 300 is one great little trouble free shotgun with loads of cheap spare parts if it should ever breakdown which I doubt.