John - I think those studs are meant to go through the spare wheel stud holes to securely align the wheel on the strap assembly.
I briefly read through the 1946 Chevy Master Parts Book and believe those threaded studs match your wheel mounting studs and take regular lug nuts to further secure the wheel to the strap assembly.
No personal hands on verification, but that what my brain tells me after looking through my resources.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
