Super Rocket cylinder head identification.

[stbusa]

My recently acquired super rocket cylinder head has two sets of number stamps. The first is standard 67-1122, the second number which I have been unable to recognise is 13B16GF.
Is this a machine shop reference as it appears to be an 'official' mark?

[JulianS]

67 1122 is usually a raised casting number and is for an A7 Shooting Star.

The stamped numbers are usually by the rear stud position as in the photo of a 67 1549 casting below and are seen on most ali heads but I dont know what they refer to.

[DerekAnderson8]

http://atlanticgreen.com/a10alloyhead.htm

all variants here

[stbusa]

This is the number that I am trying to identify.