yeah, the Phenom II X4 955, 965 and 980 are all identical chips.
Basically how the process works is certain wafers contain more stable chips at higher clocks, AMD or Intel will pick these chips and factory clock their rating higher because they found them to be less defective at higher clocks. The term is called cherry picking. Its just a ploy to get your money.
On occasion however, you might actually get a chip that could be considered a higher rated CPU and will have higher overclocking potential (sadly I didn't get that lucky)