4seventy,

What I meant is called 'Laufhaken' in German. The literal translation of that is 'barrel hook'. The example that I was shown was a 'Doppelte Laufhaken Verriegelung', which literaly means 'double hook lock', which is simply a double locking lug system (without anything else, so no a Greener cross-bolt, for example). These lugs / hooks were apparently worked on.