BD-4 Landing Gear Rubbers

I have what I hope is a simple question on the BD-4 landing gear.

On my BD-4 plans the rudder donuts that are called out for the main and nose
gears are identified as a Lord Mount (J-11968-5). There is three of these
required for each aircraft, one for each leg.

My question is can you still buy these (my search of the catalogs on Lords
web site turned up nothing). Have Lord changed the part number ???? Is
there a commonly used substitute part, even if from a different manufacturer
such as Barry.

Does anyone know anything about the specifications of the donuts ? What
rubber hardness, what stiffness (lb/in) etc.