1 of 2 Lower Control Arm pivot shaft fixing bolt broken

[usedvolvoboy]

I'm currently replacing most of the front end suspension components on my '90 MM 2wd.
While removing the 2 fixing nuts for the rearward plate of the LCA (Driver's side), one of the bolts that appear to be pressed into the frame rail sheared off.
Is this flat-backed bolt indeed pressed in or is it tacked on there? It's tough to tell.

Where can I get one of these bolts besides going to the dealership?

I'm guessing at this point that I will need to grind the back off of the bolt. I noticed that the bushing presses against this so I guess I can't just use any old nut/bolt.

Pic is attached. Any advice appreciated.

Thanks,

Jay