'73 Argosy service manual

[Ann22]

I've got a '73 Argosy 24 ft that I've had for several years now. I lived in it for 5 years and I've done some small repairs such as replacing the hot water heater, minor plumbing and such. Now I'm looking at fixing it's problems and getting it back into shape - replacing the air conditioner, plumbing, and whatever else needs to be fixed or replaced. I called Secretarial Services looking for a service manual (I've got an owner's manual) and the lady there told me there were no service manuals for the Argosy. My question is are the guts of the Airstream and Argosy trailers of that year similar enough to make it worth paying $85 (with S&H) to get an Airstream service manual to help me on some of the systems I'm not real familiar with or am I better off blundering my way through?

Thanks,

Ann