I did weigh my 525 x 98 link chain from my 1198SP at 4.0 lbs and the 3D520GP 520 x 98 links at 3.4 lbs, so a savings of 0.6 lbs high speed kinetic weight. It’s a really big deal if your doing serious weight savings.
Maybe you weighed the 3D at full new 120 link length?