crafted griddle

I was looking at a Weber Rust-Resistant Griddle Insert at Home Depot, yesterday (Part #6787). This is the full-size, carbon steel insert that replaces both grates. Does anybody know if this will fit a 2013 Spirit E-310? According to the box, it says its only compatible with Spirit 300 series...

The Crafted stone and griddle are heavy and bulky, but I wanted them to be stored in a convenient place. It took me about an hour to build a simple frame that will hold both items conveniently below my grill.