Just thought I'd add this to the thread. It isn't the center armrest, but the armrest on the door itself.
The plastic tabs that the screws hold onto had broken apart and I had thought about a way to repair rather than buy new pads. Taking JB Weld and filling the hole, I waited til the glue had partially set. I then put the screws in from the backside and let it set up the rest of the way. The pad is now securely attached and hopefully won't come off again. Price, nothing....I had the tubes of JB Weld from a previous job. Hope someone else finds this helpful.