Written by the TreasureGuide for the exclusive use of treasurebeachesreport.blogspot.com.
There are wrecks of the Manila galleons that have been investigated. You can find them described in The Archaeology of the Manila Galleons, by Robert Junco. Here is the introduction.
This paper presents a brief recount of the Manila Galleon sites investigated to date. It also proposes, some ideas of what the archaeology of Manila Galleons could consider in its research objectives. The Manila Galleons, loaded with their rich cargos of oriental goods are still a great mystery to researchers, especially those belonging to the sixteenth and seventeenth centuries. Furthermore, studies of Asian ceramics and other products of exchange in New Spain and beyond are scarce. While the work of historians and art historians has contributed significantly to the topic, archaeological studies are rare given the few sites located. In this paper, I shall mention the Manila Galleon sites that have come to my attention, and then present some ideas that I deem relevant in the pursuit of what can be termed the archaeology of Manila Galleons.
And here is the link if you want to read the rest of that article.
http://www.themua.org/collections/files/original/61b274c68e00272c5e50f0af53f5b140.pdf
You might like this story about how three students found $40,000 cash hidden in a sofa they purchased at a thrift store. Good story how it turned out.