My name is ***** ***** I would be happy to help with your "Regis Plate" container.
"Regis Plate" is the trademark of William Suckling of Birmingham, England, who were active from 1895 to 1965.
Your piece dates to the latter end of that range, either 1930s or 1950s.
Suckling made a huge range of silver plated tableware items, sold under two brands, "Regis Plate" and "Kingsway Plate". The range included a series of these containers of various sizes to hold bottles of different sorts. This one, for instance, was marketed as a wine coaster. At 4 1/2 inches, it sounds like yours is for a sauce or condiment bottle, but keeping pens and pencils in it is just as good!
"E.P.N.S" stands for Electro-Plated Nickel Silver, a base metal alloy that is predominately nickel to give it a silver color, covered in a thin layer of silver that is applied by electrolysis, a technique pioneered by the great English maker, Elkington, in the 1840s. Items marked "EPNS" started to appear in the late 1880s and early 1890s and in common usage throughout the 20th century.
The N977 is an internal factory code for the mold or design number for this particular shape and size.
This company does not appear to have any specific following of collectors but the wine coasters seem to have a steady following and sell on line for $15 - $35 each.
Yours would have an on line value (eBay etc) somewhat less than that, say $5 - $15.
I do hope this helps
PS. If there's anything more I can help you with on this, please don't hesitate to ask. If not, could you very kindly rate my services (with the stars or "accept" button) as this is how I get paid by JustAnswer at no extra cost to you. We can still continue to communicate here on this thread after you do. And if you have another item you'd like to ask me about, just start a new Question and put "For Robert S....." in the subject line. Thanks, R.