Thanks Al for the additional notes. Yes, I removed the speaker cables from the amp and it only takes a 2-second touch of the battery terminal to detect the speaker excursion. It never hurts to be too cautious, thanks.
As an aside, my buddy who had an out of polarity (Coincident) speaker problem could not get sufficient bass from his full range speakers and spent many $$ in acoustic treatments, equipment changes, speaker placement, sub woofers etc. He finally sold the speakers only to have the new owner email him asking why he didnt tell him that one speaker was out of polarity with the other. The new owner just switched the cables polarity on one speaker and he now has glorious bass.