There are two Silver R2-D2 figures.  One was a vac-metal sold carded based on the 2000 Power of the Jedi figure mold.  The second was a Saga Collection figure in a UK-only boxed set with a matte finishe, based on the Vintage 2004 mold.  The set was pretty tough to get in the USA... but now you don't need to get it.