Topic: 68 Standard arm rests

[68 S Code]

I have been looking for an original 68 LH arm rest and have run across a few but they have three holes versus just the two. The third is more towards the center but lower than the outboard ones. Is there an early and late thing going on with this oddball arm rest? repops only have two. I have an original set of blue ones with two so whats with the one which has three. Did an actual fastener go in the third hole? My door isn't set up for three.