I think the American made cord, I believe you would be fine. The imported cord, which appears to come in solid colors & the whole cord glow, I think may have chemical additives that may bleed out. I've seen two types of glow in the dark cord, the tracer type & the full white/faded white type. The tracer type is your standard Paracord with a tracer that is glow in the dark and gives the cord a rough feeling and doesn't glow nearly as good as the white/faded white type. Those glow much better & I believe longer. I made a cat collar with glow-in-the-dark cord. It's the off-white type and it glows really bright if you let it charge up in the light.
I don't know just to be safe I wouldn't I used to pre shrink as well but found out it really doesn't make to much deference your customer might get it wet from rain but not hot scolding water I just tell them if you have to clean it use cold water
FWIW, while you can find glow in the dark cord that is made in the US, the yarns are only available as an import. It's also only available in polyester. I don't think pre-shrinking it will hurt it at all.