You can do that, but a friend with RM50's has 10 Neo panels and multiple were dead when they arrived. I replaced them for him with new units from Brian. Coincidence, possibly.
Since you cannot tell direction easily on a Neo panel, or tweeter, an Ohm meter would be better for a test resistance. For a woofer, you can see the direction of movement for polarity. I have seen Neo panel DC resistance as low as 2.8 ohms. That is over 3 amps into the panel with a 9 VDC battery if it holds voltage. With a 1.5VDC battery it is less than 1 amp.
I always side on safety for components first.