VESA Adapter Plate -for Mounting a non-Dell Monitor to the Flat Panel Stand - Kit

Ive seen this on the site as im interested in the Dell S2409W but it doesnt have the type of stand i want. I was wondering if all dell mounts are the same or if this adapter plate would be needed if i was to get a fully ajustable stand from say a Dell Ultrasharp 2408WFP.