General Maintenance & Repairs - Bolt Size for tunnel brace under a 99 WS6?

Just got a BMR replacement tunnel brace and can't find the damn bolts. I will hit up the hardware store tomorrow, but does anyone know the bolt size, that would be great! Thanks.

Nick

anyone?

I know the bolt head is a 15mm not sure on the threads. sorry i cant help much.

Anyone else?

Anyone work at a dealership that can look it up for me? I don't even know if it fine pitch threads or coarse. Any suggestions?