I can't speak for Energy Suspension's offering but yes, poly bushings may squeek if not properly lubricated or if lubricant needs to be reapplied. That said, a good PTFE lubricant can last for years on a daily driven vehicle. The stiffness of the bushing material will play into how prone they are to making noise.
My daily driver is a MR2 and I've swapped out a few bushings with Prothane bushings about 3 years ago... Still no noise to speak of. Now that doesn't mean there won't be. Urethane bushings wear differently and do need to be re-lubricated from time to time. The design, characteristics of the specific material and application dictate how often this may be.
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