The Ones that have Disston on the rear are the DA211 models. They were the most popular. The one that has Kiekhaefer on the rear is a model KA211. It was the last model made. I believe there is no difference between them other than the rear cover. I belive but I am not sure that when they went to the KA211 model it was because Kiekaefer took over the entire production.
Bill
Any idea what they might be worth Bill? What should I offer this guy, if anything?