Calipers are handed, so you'll need the correct one as the top bolt has a shoulder and the hole is slightly larger, you could swap the bolts in the short term I guess to get you out of trouble but it's got a shoulder for a reason. I think you'll also need to swap the discs as they're a different thickness but I'm not sure.
I have a upsidedown one on the t25 [pickup one] ,was thinking about the different bolts ,normal cars have the same, maybe VW had another non eurika moment... btw @Top Banana Racing we are going to have a heat wave this week...
It had got beyond that stage but I had noticed a pull previously, Ted is a tall Bus and wanders under heavy braking anyway, it's my accepted trade off for being able to clear speed humps and not have my fillings rattled loose.
Not the 72 ones, bolts are both the same with no shoulder the caliper can be swapped over side to side.
I think the long term solution is just to buy new (later) ones and the fitting kit, thereby circumventing any future problems. Now to find which one of our esteemed sponsor suppliers actually has stock (rather than computer says so) of said items and can deliver it tomorrow without fail! Looks like I'm spending my wedding night working on the Bus. #start as you mean to go on.
Its the best idea, I did the same thing with late calipers as I had my O/S one seize up as well and I reasoned that if I was buying new brakes I may as well get ones that I could easily get spares for in the future, added to that I put on new flexi's at the same time and now they are superb, they shame make my MK2 GTIs brakes completely it makes you wonder where VW went wrong with that one.....
Fortunately I have new flexis already so it should just be a case of unbolt old stuff, bolt in the new and finally swap the pipe across, a quick bleed and Robert is your mother's brother.
If you don't have any luck, you can drive it to mine (?) I have a complete early disc brake setup lying on the workshop floor looking for a bus...
Good luck TBR - sure you can sort it.. Failing that i ca see the start of an " I broke down before i set off for France" thread ...
Alternately ,like top gear you can drive in your car to mine and lend the T25 ... It takes quite a good photo if your a mile away ,it even looks like a bay...