Hi, sorry for the delay, I've just got home from work.
The outside diameter of the primaries is 45mm.
I got it as part of a job lot of parts so I only know what the seller told me, which is that it came off a CSR. It's in very nice condition but I don't know the year I'm afraid.
The part numbers/markings that I can find on it are:
silencer - CSP907B.
cat - 4575, ECOCAT OY 85324, E1007507.
primaries - no obvious markings.