Volvo Penta saildrive diaphram date stamps

[wiggy]

Trying to age the diaphram on my vp 25 saildrive leg. There are two clock type moulded stamps on the diaphram with numbers around the edge and an arrow. One has 01 next to the arrow that is pointing to 4 and the other has no number in the centre and is pointing to 0.
Any one know what these mean?

 

[tawhiri]

I have just received my new diaphram, and it has 2011 molded in to the rubber.