This would be best answered by @CozyPure. I am not positive, but I would guess that they would not measure ILD on a noodle topper or any noodle product. The noodles are a blend of various latex foam cylinders. Additionally, the noodles react a bit differently than a solid core slab of latex.
When you lie on a noodle topper or pillow, the noodles exhibit a foam of displacement that is different than if it were a solid core.
Having tried a CozyPure noodle pillow, a solid core Dunlop pillow, and a solid core Talalay pillow, I’ve noticed that each one has a distinctly different feel. My wife loves both the Talalay and Dunlop pillows. On the other hand, I found the Ba-Noodle pillow to be far too soft for my preference. Luckily, I had ordered an extra pound of noodles. Once I added them, the pillow firmed up significantly, making it comfortable for me to sleep on. Since I’m accustomed to a horsehair pillow that compresses to a firmer feel, my experience might differ from that of most people.
I own and have created a variety of pillows. Having purchased pounds of noodles, wool batting, horsehair, and other fillings, I found that it’s possible to change the feel of a pillow, topper, or even a mattress. How taut, stretchy, or tightly these bedding pieces are encased will determine their performance. You can read more about my experiences here.
Though these are pillow experiences, the materials and their properties certainly transfer to other bedding selections.