Thank you for contacting Mearto with your appraisal inquiry.

It is a beautiful antique silverplated tray. Such antique trays are being offered at auction on a regular basis.
The tray is very large and this particular style and type of serving tray was very popular in the early 1900s. The material it is made on is like you describe silver on copper. Also known as silverplate - this too was often used and in particular on very large items like your tray. It appears to be in good condition and due to its size I believe that it would attract the attention of both collectors and dealers if it came up for auction.
The decoration and the engraved initials on the front is also typical of this particular era and style.
I cannot see the marks clearly enough for me to say who and where it was made but this particular type of household item was popular worldwide in the wealthy houses during the late 1800s and early 1900s.

The estimate provided is for a well-advertised specialised online silver auction, where I believe the serving tray has the best chance of realising its fullest potential. However, there is no measurement for the sentimental value you might attach to the tray. Retail "asking prices" can be higher and vary.

Please let me know if you have any additional questions. I’m happy to help.
Thank you