I actually doubt that, most likely course of action for fuckery specialists over there is to help act as force multipliers for standard Ukrainian forces. There's probably green berets over there helping train soldiers and insurgent paramilitary forces over there in safe zones, also probably leading excursions eastwards to set up caches of supplies to help set up stay-behind operations. But for actual wetwork operations, I find the possibility very low as the risk that operatives could be captured and be identified as american saboteurs leading to a possible escalation of force outweighs any sort of gains that could be acquired from deploying wetwork fuckery specialists.