It is a vintage acoustic Silvertone, and the seller claims (somewhat vaguely), "This type of guitar was used by Elvis Presley during the early years of his career." Note that he says "this TYPE" of guitar, and not this EXACT guitar. And were really not convinced that Elvis played that many Silvertones.
But what's really interesting is what the seller says next: "I received this guitar from Elvis in 1956 when I was twelve." We tried to contact the seller to get more information about this unusual gift, but have so far received no response.
The whole thing sounds a bit iffy, and paying the "Buy It Now" price of $1,000 may be risky, but hey, the seller offers the high bidder a "noterized affadavid", so what more could you need? Take a look at the guitar here.