It looks like my spacer comment didn't make it up. I hope this isn't a duplicate.
Armando, I believe those to be the wrong (albeit usable) spacers with talking 914-6/GT variety.
We've restored numberous factory GT calipers along with what I believe to be the very first GT caliper ever put on a 914-6. These calipers use the spacers and hardware from the eraly 911 rear M-Caliper. They have a more crude, machined, rounded appearance than the ones you have there.
While this may be picking nits, the ones you have there are the later "cast" spacers that actually fit the caliper profile in a more exacting manner. These are either from a later Ferrari caliper or a later 911 rear M-Caliper.