caliper retaining bolts testarossa

not too sure how this happened, taken all 4 calipers off to be rebuilt. yet when i went to put them on i seem to have a wrong size bolt left to fit on refitting last caliper. it wont fit through caliper or thread in hub[ but fits the threads on the hub towards front of car, ie if calipers were font mounted ] and same 19mm head as others, it seems a slightly larger size than all the others across thread. went around all others presuming fitted 1 wrong elsewhere yet all tight.well confused and all parts diagrams show 2 types of bolts yet mine appear the same, front and rear. they seem a fine metric thread, maybe 1.25. well confused here and ferrari/ricambi price each at £34 each. any help appreciated.

 

hiya, know what you mean with the washer/ shims for spacing the calipers out. 7 seem to be the same and 1 slighly larger,didnt suss it for a while as thought spacer shims were being troublesome. but even after taking the caliper off still wont fit thread in hub, and neither thread is stripped/mullered. but will fit if forward mounting the calipers. using the other threads in hub..and trying to locate a 12mm fine thread bolt isnt very easy, dont know whether to remove all calipers again to re check but all other bolts are very tight, my mate came round thinking i was an idiot but he cant work it out either.