Dave
A quick search found one at Dodson. Also there is a Skymaster G model being parted out in Middleton, Ohio. Is this housing specific to G model or will another model work? I will do a little more research
Looks like in the PC for a 1976 the barrel number is 1442112-3. here's the whole assembly from Texas Air Salvage
http://www.texasairsalvage.com/main_...?editid1=29314
If the 1442112-7 works for your model Dan Booker is parting out a 1969 that might have one.
Here's a barrel from Spruce in Europe
http://www.aircraftspruce.eu/barrel-shimmy-dampener.htm
1442112-496
Price: Call
Quantity: 1
Kansas, US
Condition:RP
SHIMMY DAMPENER
Dodson International Parts
Phone: (785)214-4310
Fax: (785)878-8800
Updated: 8/6/2013