If SPD is programmed to DDR3-1333 but DIMM advertized as 1600 you can safely assume it's based on cheaper but heavily overclocked/overvolted DDR3-1333 chips instead of native 1600 chips. That's nothing I would buy. (values just taken as example). I remember DDR1 times where RAM requiring 3.2V (instead of standard 2.5/2.6V) was sold - OCZ and GEIL were prominent members of this voltage gamble. Gamble continied with DDR2 and up to 2.1/2.2V instead of 1.8V standard.
They couldn't continue this with DDR3 as Intel could not guarantee a safe operation of their CPU at RAM voltages above 1.65V, AFAIR starting with Core I-series.