Hi Mark,
Its going to be a matter of fit, adjust & repeat.
I dont believe the 1163 case ever ran these block bracelets from the factory.
There are 2 different profiles for the 11630 case & the GMT uses the "fatter" of the two profiles so it could well be that the end-pieces you have will be intended for the other 11630 profile.
I recommend you first open them up gently to be too large a fit & then place a piece of rubber over them & pinch them down until they have a tight fit. ( Note - ok to use plyers on the rubber to pinch them closed if your fingers cant close them enough )
Good luck - Darren

Here's an 11630 i have on this bracelet

: As stated in my earlier post: I bought the watch with bracelet and
: endlinks. Sent it to my watchmaker. I'm not sure whether I
: included the endlinks, watchmakers does not know whether he
: received them, I can't find them, he can't find them. Some had
: endlinks of which he was sure the were for a 1163(0). They look
: the part but after receiving them they seem not to fit. Can
: somebody in the know help us: is it either a question of bending
: them to fit or is the case profile of a 1163 so different that
: this will never work?

:
:
:
:
:
: