rear caliper brackets

[markovr]

Picked up some 315 rear brake discs cheap lately and noticed after some searching that the normal 315mm setup that uses a pbr vt style caliper looks like the same caliper as the 290 one with just the cast iron bracket being the difference..i was just wondering if it is possible to buy the brackets as a spare part.

 

[TI3VOM]

They're 280 aren't they? I imagine a Holden dealership might know, otherwise get some custom brackets made up.