Irrelevant. They can still use them right away with no modifications.No, they will not. The Polish MiG's have been refitted to NATO standards. They have glass cockpits and avionics that are in English, NATO IFF and NCTR, fire control computers, and databus.
They are made to be interoperable with NATO air forces, not Ukraine's. They can fire R-73's (IR guided), but I don't think R-77's (Radar-guided).
A Polish MiG would identify a Ukrainian MiG as an enemy fighter.
They would have to be converted back, or the Ukrainian pilots and maintainers would need to be retrained. It wouldn't be a rapid integration.