Silver or Silverplate 3 wine decanter holder

I am hoping that this piece is American as I am familiar with the British silver. It is heavy - 4 lbs exactly. I have been treating as silverplate as the only marks I can find are S 4989 (pattern ?) and a hortizontal lozenge (diamond with small circles on each point with 44 in the middle. Is this a correct assumption? I know sometimes C or D were used for marking the type of silver. Was S? This is old piece with it’s original bottles. From the mixture of flowers, grapes, deer and filligree I would place in mid - late19th century. There is no EP on anything.

Just as aside…how do you suggest to effectively clean something like this? Silvo is working. Some of the milder washes don’t work. I’m allergic to Tarnx.

Thank you for consideration on this topic.

Generally speaking, all American sterling silver made after about 1850 will contian the words “sterling” or “sterling silver” or “925” or “925/1000 FINE”. American solid silver made prior to about 1850 was mostly ‘coin silver’ or 90% pure silver and contained the word “coin” or “90”, but sometimes was unmarked as to purity. It is generally safe to assume that if it does not bear a purity mark it is silver plated.

Regards,

Uncle Vic

Thank you.

Sounds like a British Registry Design mark. Check here:
925-1000.com/registry.html

Thank you for the link to the Rd Nos. No it is not one of these. I think it is probably a silverplate mark. However, your link enable me trace an Art Deco salt set I was trying date. 1923. Thank you again.