Gudday

I just bought a 1200 ute with an a15 engine.
I have plans to refresh the running gear and am starting with the brakes.
The ute has discs on the front and runs a bendix brake booster with a tandem master cylinder which is very tired.
Through researching this site I found that brake master cylinder jb1117 would be the right replacement for this and ordered one from a online brake retailer.
The brake shop sent me an email back with an image of their catalogue staring that part number jb1178 would be the right part for a drum disc brake setup.
Before I confirm the order I thought I would throw the question out and see if anyone has had this same situation.

Any advice would be appreciated.

Apologies if this has been covered previously, I did a search but couldn't get a solid answer.