okay from what i've found on calibre 12 (engraved on top of back case as you can see in image):
http://www.boley.de/en/kaliber/kleinuhrwerke/maurice-lacroix/9834?q=maurice
and according to that :
brand MAURICE LACROIX caliber 12
size 10 1/2 function SS
version 1 Eyes (6) hands 0.80x1.30x0.27
stem 5029 stem (subs.)
stem (2 pce) 22001 /f.Schr.Reif 0.90
balance staff 22003 / Spiral-Ans. 0.80 balance staff (subs.) 22004 / Spiral-Ans. 0.45
mainspring (subs.) 1.0x9.5x0.12 mainspring (subs.)
battery
Artno. brand caliber size special function hands
156700
ETA 7001 10 1/2 1 Eyes (6) SS 0.80x1.30x0.17
partno. caliber description Artno.
401 Winding stem 8025029
723 Balance staff, pivoted 80222004
723 Balance staff ST -shock-absorber 80222003
So, not sure if my Googling skills were on point, i also find no info on ETA 2876?
Please correct me if i'm mistaken....