Answer: In a quick search I was unable to locate information specifically about that lilac except a brief mention indicating the hybridizer as Dunbar and the year 1916.
However, you might be able to find something about it in the book "Lilacs - The Genus Syringa" by John L. Fiala (Timber Press) or perhaps through the Internation Lilac Society at
You might also try contacting some of the other lilac collections across the country to compare notes. The Society web site includes a listing with contact information to help you get started.
Best of luck with your restoration project!
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