Hey there - sorry about the delay in getting back to you on this. Through a bit of searching, I came across this entry in a book titled The Whiskey Treasury written by Walter Schobert:
"Adams Canadian blend from Seagram. This brand was created by Samuel Bronfman after he had bought United Distillers Ltd in 1953 and changed its name to Thomas Adams Distillery. The new name was a reminder of a whisky pioneer whose distillery was licensed in 1802. There are several versions: Adams Double Distilled contains at least five-year-old rye whiskies, Adams Private Stock contains six-year-olds and Adams Antique is twice as old again. There is also a Four Roses, which shouldn't be mistaken for the Bourbon which, confusingly, is also from the house of Seagram. The Adams whiskies are rarely found outside Canada. This book will be the first reference point for the trade, historian and lover of whisky and will bolster any whisky bookshelf in the English-speaking world."
So, it sure sounds like you might have a gem on your hands. I can try to dig up some additional information for you, but Whisky.com does not provide valuations. Try contacting McTears.com or Bonhams.com for a value.