No such luck, Jeff. I checked.
It seems like the previous owner used them for some time without noticing, both arms look to be a similar age & condition. They're annodised blue, a colour I've never seen before on these cranks.
If one arm broke, they managed to replace it with another blue one somehow but couldn't get the right length, or thought they had.
Or maybe they were mismatched out of the box.
Guess we'll never know.
I'll keep an eye out.
The seller says they'll take them back but you just know a spare arm will become available the minute they're posted.