[freakray]

Yes you can.
Will it change the finish, yes it will.

Now let us ask you some questions, when did you spray the silver leaf and what type of clear do you plan on using.

With Tamiya clear, unless it is applied directly after the final coat of color, you need to wait at least a month to clear coat - this is because the Tamiya clear has a different cure rate to Tamiya color sprays.