Hi Cliff
yes quite sure about the fact that it is not a designed offset.
This webers are die cast. Only the first ones where sandcast.
After casting the barrels are machined. So any offset or centered placement is just question of correct or as in this case uncorrect machining. No changes of mould necesarry to correct this, only good machining.
this is how it should be. I could take a picture of my other pair of IDA´s both of them look like this. So defenitely bad quality of the "made in spain" stuff.
TOM