The harp is a Seydel Session Steel - and Seydel makes awesome harmonicas! It is the exact same reed plates as what you can get from Seydel currently. The comb is the black Session comb, and the covers are the same antique covers you can also order through Seydel, however, the Popper Signature harmonica does have a lacquer baked on the cover plates to make them glossy. It also eliminates any taste from the antiqued plates and cuts down on friction. Finally, the JP harp is slated to come in 7 keys, whereas the Session Steel is available in 18 keys (John uses 14 keys and Fender is making him the additional keys....but honestly you can part the same thing out through Seydel anyways)!
You can buy, structurally, the exact same harp through Seydel with the stock Session Steel for about $60, whereas the Popper Signature will run $99 MSRP. The Fender John Popper Signature Harmonica will be available sometime around May. The Session Steel is available now!