The Audley Safety holster had a spring loaded safety catch that locked into the trigger guard and had to be depressed to get the revolver out of the holster. Revolvers that went in and out of Audleys had wear on the trigger guard and I suppose some might cut down their trigger guard to get the revolver out a shade faster or easier.
This shows the inside of an Audley made for a 4" .357 S&W. The safety catch is visible on the right side.
Front shot shows the position of the safety catch.
Regards,
turnerriver