If you will .... note the date -12/7/78 -on the plans.
In the introduction to the "booklet", Rudy is mentioned in the past tense. There is also mention of earlier dealings with
Popular Mechanics and
Mechanics Illustrated though no dates are mentioned. There are plans for five steam engines and one Revolutionary War Cannon in this edition.
The credits read as such... and I quote ...
"The plans herein are made available through the courtesy of Susan Alvaro, Rudy's heir. The help of Walter Yetman was crucial to the compilation of the materials and photos. The lead-in photos used for the various sections were taken by Craig Libuse who an was instrumental figure in the display of Rudy's engines at the Joe Martin Foundation Museum of Craftmanship."
.... end quote.
The ISBN Nos :
ISBN 13: 978-0-941653-28-2 and ISBN 10: 0-941653-28-5 and is copyrighted by Village Press, Inc.
The cylinders are 'suspended' within the collars situated at the midpoint of the barrels and work in the normal wobbler tradition

.
Hope this helps.
Cheers.......
Collbee.