From F to K all Bf 109s had 1 Cannon firing though the prop hub - either MG 151/1.5 or 2cm or Mk 108/3cm. There's no way 2 or more cannon could fire through the hub.
I am not familiar with the exact load-out of Weißenberger's Bf 109 G-2 but three MG 151/2cms would indicate 'gondolas'.
See
here.
Regards,
Bruce