You can recognise the Venice core by looking at the Heatspreader on the processor - look for the ending DAA4BP for E3 Venice or DAA4BW for the E6 Venice . The heatspreader is easily visible through the AMD Processor box window. Have attached a pic for you to understand what I mean:
San-Diego is the E4 stepping. It exists on the 3700+ and 4000+ models. You dont get it in the lower end 3000+/3200+ models.
E6 stepping is just an enhanced/tweaked version of the E3 core.