Given that it's a Canadian blend of relatively young age, I would suspect the value may be more in the rarity of the bottle itself than the whisky inside. I think we'd need some more information...
1 - Is the seal still intact with no signs of evaporation?
2 - Are there any details on the label that might indicate something that could add to the value as a collectable?
3 - What size is the bottle, and is it in an unusual shape.?
Not knowing any of these details, my suggestion would be to look on eBay for comparable Seagram's bottles from that period. You might also consider trying an auction yourself for this bottle to let the market determine the value.