[BGP Spook]

Under standard conditions of 1 atm, and 1 M worth of ions in solution.
Ag+ to Ag has a reduction potential of 0.799 volts.
Cu++ to Cu has a reduction potential of 0.337 volts.
Sn++ to Sn has a reduction potential of -0.14 volts.

If under standard conditions with Ag used, then 0.799 - 0.337 = 0.662 volts with the Ag as the cathod. Therefore, the Cu would dissolve and the Ag would plate if a reaction were to occur.

I think it is important to point out that you will almost certainly see little reaction unless you introduce a large amount of some electrolyte.

But maybe I am wrong.