The full serial number for my '60 or '61 is 22TDS0443 I took some pictures and posted them in the file area under http://www.egroups.com/files/AirstreamList/John+Ross/ (also see below). And yes it does have a solid axle with leaf springs. The original axle had hydraulic brakes that coupled to the tow vehicle brakes but the axle was replaced about 3 years ago with an electric brake axle. Click on image for larger picture
John Ross