Victorian Door Knocker Registration & Foundry Marks

Hi,
Trying to read the registration and foundry marks on this door knocker.
I think the letters are CJS for the maker
For the registration mark I think there is a 2 and g
Not sure if this would be brass or bronze?
any ideas appreciated!
thanks for looking.

 

Brass, and British so probably made in Birmingham.

 

Thanks bear! I found another one with the same marks and they say it is pre-1884. I can't make out the marks on theirs any better than mine.

 

The diamond mark was replaced with the registered number at the start of 1884 so it would have to be pre 1884.

 

Looking at the mark above the capital R it looks like a 2, as does the mark to the left of the R. If so, that would be the diamond mark applicable in the period 1868-1883, though one would need to decipher the letter to the right to get the year.

 

Very nice , CX !!!!!

 

Thank-you rhiwfield, you have better eyes than me! So I'm safe to say it is old

 

Original registration marks would have been used till they broke the mould, so it could have been cast years after the original registration of the design, but late 19th C seems close enough.