This collector's plate is the "Wednesday's Child" plate, the first issue in the "Children of the Week" series by Hungarian-American artist Dora Leder, produced by Kensington, Ltd. in 1980. 

Key Details from the Back Stamp:

• Plate Number: Number 2911 (out of a worldwide limited edition of 22,500 plates)

• Artist: Dora Leder

• Series: "Children of the Week" (First Issue)

• Maker / Commission: Kensington, Ltd. (Produced in the United States)

• Year: 1980

Having the original box, Certificate of Authenticity (COA), and original inserts slightly stabilizes the market value, but it does not significantly inflate the price because of the large edition size (22,500 plates).

The complete package typically sells for $15 to $25 on resale marketplaces like eBay. 

Value Breakdown

• Plate Alone: $6 to $13

• Plate + Box & COA: $15 to $25