I, too, believe the ESP stamp is for electro-silver-plate, and from the design, I would guess these are worth keeping. A slightly little known bit of history...
Back in the pre-union and arts and craft sort of days, groups of tradespeople and artisanas formed communities that were akin to guilds. Many were religious in origins. The Oneidas believed Christ would soon return and they'd all be free of sin, and thus didn't need to live with the usual moral restrictions. They were into free love, communal conjugal opportunities and such. It was a Utopian society that practiced Communalism.
This does look like an older style piece and I would hang on to it (and just because it the term "electro" is used, doesn't mean it's "modern," as electroplating was possible in the late 1800's) .
Thriftily,
Alexandra
www.livingwithoutmoney.blogspot.com
