(Helen) Here's what we know: When Dörfler & Jörka was bought out by J.Keilwerth around 1965, the partially finished saxophones that Keilwerth assumed from its takeover of D&J that had not yet been engraved, were given Keilwerth key guards and a traditional neck fastening screw. The D&J saxes that already had their engraving, were then assigned a Keilwerth serial number.

H. Genet had ordered stencils from Dörfler & Jörka. Like the Jubilee horns shown in this gallery, we can't say with 100% certainty if the bodies were made by D&J or JK.

Regardless of who made the body tubes, the horns played identically, and are kickass saxophones. (I speak from personal experience as the owner of JK tenor, and the former owner of a D&J tenor.)