This isn't about design, but I'm hoping someone can help  

Try an Ebay discussion board
The Ebay "Antiques" board is lively and the posters seem pretty knowledgeable.

Nothing I've read
would make me think this could not be bronze. . .

a Photo.
Describing anything visual in words is hard to respond to.
A photo, even if you think it cannot show its merits, does
give tell-tale signs to some that have seen this before...
And yes. E-bay has a forum section that is scary active!
A better forum for you to look and ask for advice. But they
want photos as well.
A long descripion is not that valuable. A photo with a close-up of
casting details are actually interesting to a collector. And interesting
to someone with experience giving advice.
Your enthusiasm is fantastic and charming. E-bay forums have a wealth of
knowledge for odd requests such as yours.

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Green spots
Dots, I don't think sold bronze tarnishes into green. Tarnish usually implies copper, silver, brass, etc., not bronze. Can't you even give us a hint what you are talking about, i.e. size/shape?

.
Bronze is largely copper...are you sure the undertones are not gold/brown...

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.
looks like what I've heard called 'rose brass', which is brass with a higher proportion of copper. May well be wrong though.

Spelter - lead weighted?
Spelter - lead weighted?

Why can't you post a photo...
Why can't you post a photo of the whole thing if you can post photos of parts of it? Are you just dicking everyone around?