Thought from the image yours was missing the lower tabs... were they removed with a bit too much force? 
Mine deffo has that smooth ridge/indent along the top edge. It has a ridge both ends but only screw holes at the front. Can't recall what the ident is.
The matey said he had a anniversary taken to him after 2 lads stole everything off of it except the tigerseal was to strong for them so the sides were left lol
Can someone post a picture of the stamp on the anni skirts and a close up of them please cause a chap on uk mkivs said there votex as the stamp has ms designs on it the votex distributor and the other type thats been referred to as votex are apparently r line skirts a similer version to the r32s