I'm happy to answer your conservation/preservation and materials identification questions.
It would be best if I could see at least two or three photos of the object so I can best judge the condition. Detailed images of any markings or trademarks would also be helpful.
These are not that rare, however, yours might be a less common variation. I found one on-line with a horse finial that was going for $1000-$2000. As an objects conservator, I have conserved several of these in museum collections associated with various families over the years. A museum might be interested in yours if it has a historic provenance.
As for cleaning, I'll reserve full judgment until I can see the actual condition. In general, it's probably best not to clean silverplate at this point because probably not much of the silver is left due to previous cleanings. Re-silvering is always an option, but you will no longer have an original antique, so I would discourage that approach.
If you cannot attach images by using the paperclip icon in your response window, please contact JA technical services for help. I'll await the photos.