"Foreign, northern artist": original by Filippo Napoletano instead?

Bertolami, from Italy, offers on 15 December 2016 a "Foreign artist active in Rome, 1st quarter of the 17th century" Allegory of Luck, estimated at 25,000 to 30,000 Euro. The remainder of the description makes it clear that with "Foreign" they mean post-Caravaggio painters from Flanders, France or Germany.

The original of the painting however, is made by an Italian: Teodoro Filippo di Liagno, better known as Filippo Napoletano; the work, from 1617-1621, is kept in the Palatine Galleries in Florence. It is called the "Man of Snails" or "The Snail Seller". This painting is only 18 by 13cm though, while the work for sale is 95 by 75 cm! 

The work has been copied, one is e.g. for sale in Russia for 675,000 Rubles (about 10,000 Euro), but is clearly worse and in poor condition. That version was for sale at Holloway's in 2013 with an estimate of £1,000 only.

This version though is not a mere copy, as it is different in many details: not just the colours, which might have been caused by a copy after an engraving or drawing, but also the attributes on the table. The cat on the right side of the seller is also much more clearly visible in the work for sale than in the known Firenze version.

Which brings us to the main question; is this a copy, an alternative version, or even the original version? If it is a copy, the estimate is clearly too high. If it is the original, I guess it could well reach 50,000€, as people like to have a name for the artist, and having another version in a major museum isn't too bad either.

UPDATE: sold for 37,500 Euro, above the highest estimate! I guess a few people hoped (or knew) that this is indeed the original.

UPDATE 2: for sale at Hampel on 26 September 2018, with an estimate of 25,000 to 35,000 Euro again. Described as "17th century painter" (no country), but with an Italian title. No mention of the link with Napoletano. I guess the previous seller hoped that it would be the original, but that on closer inspection this still seems dubious?