Identifying Bren Tripod

[ronstig]

Hey guys,
I've got a Bren tripod, and I have no idea how to identify it. It has the AA legs so I think it's a MK.I, but I've looked all over and can only find 3 different markings.

what looks like, 68 53 30, is stamped all over about 5 times.
I assume the 'B' is BSA?

Any ideas?
Thanks guys.