International Silver Tea and Coffe

http://www.925-1000.com/silverplate_I.html
I think this is pretty common silver. I was under the impression it was solid silver, but maybe it is plated. Can you tell me?

There are a number of pieces, all are the same pattern Cammile.
There is a large tray with handles.#6081, a coffee (6002) and tea pot. creamer and sugar bowl with lid..I am having a hard time reading number on some but they are the same pattern.

What does the R mark stamped near mark stand for?
(I used to know this but can't remember)

Just need a general idea of what it's worth.

Thank you.