Erfurt Artillery Rebarreled by Factory?

[CPT Hello]

Hello everyone,

I've come across what appears to be a (possible) matching example of a 1914 Erfurt. However, there appears to be a notch in the top of the frame (please see pictures below), looking to me suspiciously like this P08 used to have a longer artillery barrel and rear sight. If that's the case, would Erfurt or any other factory in Germany have rebarelled such a pistol (perhaps in order to comply with Versailles)? Or is this the work of a gunsmith or worse in a more recent time?