I am sure there was something for this. At my previous company before the separate source and compile code option existed I used a scripting property to check the Modification bits to look for VI's that only had "recompiled" as their change. Cannot remember what I did thought.
EDIT Just found it, I would list all the files in a directory then open one VI at a time in edit mode and then there was a property values of the VI showing "Modifications -> Block Diagram Mods Bitset" , "Modifications -> Front Panel Mods Bitset" and "Modifications -> VI Panel Mods Bitset". I had to play around a little to find out what the values meant but I did get it working