Is F. B. Rogers Silver Tray 6377 Sterling?

Answer 1

No. That particular pattern is electroplated silver on a base metal (probably copper). FB Rogers Co. made good quality silver plated products that feels like sterling due to being very heavy and durable.

There were only a few patterns made of real sterling. The registered pattern numbers are 118, 142, 144, 149, 164, 250, 400, 700 and 1636. The genuine silver version will have the word "Sterling" stamped on the bottom of each piece. If it doesn't say "sterling," it isn't.