FYI, hope you find this of interest:
Black - Wikipedia,Starr%26_Frost
Based solely on style I would date the tray to having been made in the mid 1920’s to the mid 1930’s.
Does anyone know what the numbers and the hallmark after the numbers represent?
Do either or both the 17 and 20 match dimensions by chance? The middle number was most likely the model number so they could get the correct forms off the shelf. Tiffany had what was probably the most detailed numbering and hallmark system - most pieces by them indicate the term of the president of the company the piece was made, the model number, sometimes a dimensional reference, if it was part of a set and an order number that can often reveal when a piece was made (to a specific year.)
The platter measures 14 x 20.5. Is Tiffany and Black Starr and Frost connected?