LG100 bloop tube question

[SDplinker]

I have a LG100 barrel on my Marauder. It has a hole about 1/3 of the way from the muzzle. From reading it sound like this hole was involved in a bayonet mount fitting for the bloop tube on the 10m Steyr. Was this fitting integral with the A-frame mount on the original Steyr? Trying to figure out if this same bloop tube (if I can find one) could be mounted in a similar fashion on my rifle or if it's dependent on the aforementioned A-frame.

Pic of my barrel showing hole location:



Picture showing factory fitting (can't find any pics of what's going on under that frame area):



Thanks,
Casey