Hi Pete:
Yes, stress can lead to increased mast/seed production in both conifers and hardwoods. However, conifers, like hardwoods, display natural, cyclical bumper seed crops too.
I can't tell you if you tree is under stress -- that, my friend, I will leave in the hands of an urban forester, horticulturist, or certified arborist who can conduct an on-site visit and assessment of your blue spruce. Alternatively, contact your local provincial forestry office.
More than likely nothing -- just make sure the tree receives adequate supplemental water during periods of high heat and low precipitation!