I am not an expert on 17th century ceramic styles, so I will not comment on that part of your question. However, I think you can very reasonably take David Jacoby at his word here, for writing that this object did not belong to Marco Polo and was likely not from the Song dynasty. Very generally speaking, the 19th and early 20th century Western “connoisseurs” of Chinese art lacked the expertise which has been built up in more recent decades. As long as there has been an art market, there has been a market for forgeries, and plenty of mislabelled items along the way. Early Western collectors of Chinese art lacked the depth of information currently available to make claims about an object's authenticity. The association of this particular object with Marco Polo, as claimed by the “learned amateur” M. P. Grandidier in 1894, may generally be considered less trustworthy than the re-examinations conducted by modern scholars with more information and technology at their disposal.

Modern technology has played a huge role in helping museums judge the authenticity of their objects, and accessibility to information has made it easier to detect forgeries, find stylistic similarities with which to judge provenance and authorship, and so on. It is easier now than ever before to group together 1,000s of high quality images of items from the past, and find patterns in those images, which can be used to inform authenticity claims. This is a painstaking and ongoing effort, and if you are interested in seeing how these kinds of authenticity debates play out, I encourage you to look into the comparatively public debate over the painting “Riverbank,” supposedly by Dong Yuan, in the collections of the Metropolitan Museum of Art in NYC.