I have a few pairs that match your description.. In the EU though.
I have a pair, did a complete revision on one but didn't have the tools to unscrew the second so I put them away for the time being.
Have to look where they are, you ideally need an impact wrench for the second one it won't turn with a regular screwdriver. (for me as I didn't want to force the screw)
Found the one that's ready, can take look tomorrow where the other one is.