IMO this is a previously recognized style. This forger likes the inscriptions. I think he is also responsible for many of the Mantle items that have obscene inscriptions.
If you start with the signature, this looks real to me. Obviously it would be unusual for Mantle to sign just the top half of the sweet spot. As for the inscription, it is signed in the effeminate writing that Mantle inscriptions appear in. I am going to say this is good all together.
I did start with the signature in this case, and it looks off to me. The inscription makes it worse. here is an example that I would not mind owning, and I see major flaws in the posted one, when compared to this: