How one would determine polarity of Altec 808-8G ?

"I also noted that the metal nut/cap that clamping the speaker cable onto the speaker had an dash stamped on top."
After looking at different Altec HF drivers. I found that the dash was actually a number 1 and the other cap had a number 2 stamped on it. I gathered that number 1 is positive and number 2 is negative.

Thanks for your inputs. I used 3 volts and observed the diaphragm moved forward. It easier to see diaphragm movements if you let the light shinning on the diaphragm at certain angle. I also noted that the metal nut/cap that clamping the speaker cable onto the speaker had an dash stamped on top. It looked like a negative polarity sign but it was on the positive speaker tap.