Garnett, I understand your interest in having those drawings--apart from the historical interest, they are often elegant depictions of the mechanisms, sometimes very different looking from the actual finished product.
Only things I can suggest are: 1) Looking for similar patents held by the J. Stevens Tool Company bought by Savage in the 1920s (Stevens made hammerless single shot shotguns--Model 180--and Savage may have used patents it acquired with the purchase), and 2) asking on the website
www.doublegunshop.com/BBS, which is a site specifically for double barrel enthusiasts, but has a lot of very knowledgeable engineers and patent attorneys that read and contribute. They are also a very welcoming bunch, for the most part, and have discussed patents of various guns in the past. You would have to register on the site (free) and preface your request with an "OT" as in "Off Track" to let members know you are introducing a topic that's a little bit different than the usual (there are many OT questions asked). The BBS has a "custom and single barrel rifles" subforum that has also discussed the 219 at times.
Another possibility is that no new patents were introduced for the 219/220--Savage just used patents it had already acquired for break-action shotguns like the 5100 or earlier models, since the mechanisms are similar.
Hope you can find some blueprints for your book!
Respectfully,
Mike Armstrong