The firing pin spring shouldn't be compressed. The whole idea of a snap cap is so the firing pin can be "snapped" to relieve spring tension without any chance of harming it. The ejector spring should be fine if left compressed.
In practice, a Remington 700 won't be harmed by releasing the firing pin for storage, so there is no need for a snap cap at all. In fact, that rifle can be dry fired indefinitely with no harm to the firing pin or any other part.
Jim