Rudder work could be explained with a spar crack fix, which my aircraft had. The old spar comes out and they fit the new 'split' spar in that is then closed up with tabs when done.
Your mechanic can quickly see this by checking into the rudder from the top hinge, if there is a quarter sized hole (one tells me), this is the old spar, if not, it's a new one that is much stronger.
You should also see the rivets on the front face of the spar where the tabs are attached.
