Postby dognose » Wed May 22, 2013 3:49 am
Hi Frank,
They're plated I'm afraid. They were made by Alexander Katch, a German, who set up a factory in St Petersburg in Russia in the second half of the 19th century and was in business there until at least c.1910.
The 'GP' stands for 'Galvano Plated'.
Trev.