The Volvo Aero bars are T track bars
I think the T slots are standard, so the bolts ought to be too.
In fact, I believe the "Volvo" bars are actually "Thule"
Take a look here for more info
https://www.amazon.co.uk/Summit-t-tr.../dp/B00YY31E4A
(other on-line retailers are available).
Alternatively, try one of your bolts on someone else's (Volvo) roof bars??
Cheers
Dave