I agree that they look like the Garden Railroad magazine pull out plans, but far from a complete set. I don't see any of the 1:20.3 or the 7/8n2 stuff Ted did.
As for availability of the GR plan sets, to the best of my knowledge, they are no longer available. Garden Railways stopped selling the plans years ago and turned it over to another company, A fair time ago I tried to purchase from them, the web site was there, but no one was home.
Since Kalmbach bought GR, and folded it into Model Railroader I don't remember one LS article since. I don't subscribe, but do check the news stand when I go with my wife to chase her geneology magazines.
Several years ago I redrew some of the 1:20.3 rolling stock and the plans are posted here GR Plan Sets
I have about 75% of the original Ted Stinson drawings, just never go around to updating all of them