We've had cases in the past couple of years where the rebulders flipped the Right side outer half and mated to a Left side inner half and vice versa.

Here is a link to a post about testing a "new" rebuilt Girling front 240 caliper to make sure the two halves weren't mismatched by the rebuilder.



Of course it would be obvious, if either outer half has a punch-mark "dimple" on the top, near the center joint. (Correctly matched halves are both punch-marked on the bottom.)
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.