Update on the upper plate: After someone commented on this plate looking for some info on one she has, I found out some things. After checking the back of the plate, I found out it was manufactured by The Sebring Pottery Company, in 1948. It is the Chantilly pattern, IT S284. The back also states "Warranted 22 K Gold". Which I assume is the 2" wide gold filigree trim around the edge. I only have the platter, and 6 dinner plates. Here are a few sites that list this pattern:

