If winteriezed correctly, launch boat and enjoy the day. No reason for a boat to not be turn-key ready for new season.

With that said, some shops choose to leave boat engines with plugs out and hoses disconnected, in order to relieve them of liability if an owner chooses to launch boat for an early spring run, then not re-protect engine and another cold snap happen, and block freezes and cracks.

So unless you know the state that the engine was left in during winterizing, its best to talk with shop that did the winterizing, to find out what needs to be done for making it ready for summer.