6x7 shutter speed dial ring?

[Chris Stoddart]

Hi, does anyone know where I can get one of those wee knurled rings that 
sits between the metering prism and the shutter speed dial on the 6x7? 
Or does anyone actually know what the part number for it is?

I've mailed Pentax UK and they need a part number. They first sent me 
an exploded parts diagram booklet for the 6x7 and then the same for the 
metering prism, and despite the ring being clearly visible in the cover 
photo of the 6x7 booklet, the blasted thing doesn't seem to appear in 
diagrams for either.

If you've got one, could I beg you take a look and see if it's got 
a part number on it? If you've got one for sale... even better! 
Incidentally if anyone wants the exploded parts booklets for either the 
6x7 or metering prism in pdf format, just drop me a line?

Cheers,

Chris