When Campag went from 151 to 144mm bcd they simply took 151mm ring blanks, and drilled the holes 3.5mm closer to the inner diameter. That means that, as you discovered, the rings will sit on either spider, but the bolt holes won't line up.
This gives you a quick visual check that lets you identify the bolt circle of old Campag (and compatible) rings at a glance. The bolt holes of a 144mm ring nearly touch the inner diameter of the ring, while the 151mm versions have a fair bit of metal inboard of the hole.
The left-hand ring in this picture is a 151mm bcd. The right is 144:
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De ce silence profond.