In this series of images, the Platinum series will be shown on the left, and the Gold series will be on the right.
Below we see the memory still in its packaging. It's nearly impossible to tell the two apart from a distance, as they use the same blister pack and cardboard insert. The only difference is in the modules themselves, which have either platinum or gold colored heatspreaders, and the different specifications printed on the labels.
Below we see the two sets removed from their packages. The OCZ XTC heatspreader looks pretty sharp, and makes these modules stand out in the crowd. OCZ claims that this heatspreader design helsp with cooling and stability, and if you don't believe that it makes the memory run cool, you might agree that it loooks cool!
Each module includes a sticker that details the model information, as well as the basics of the memory's timings. Here is where you can see the discrepancy with the Platinum I mentioned, where the module actually says 3-3-3-12, but the website says 3-3-3-15.
And finally, below we have all four 512MB PC2 5400 XTC DDR2 modules. This might be the best shot to use to tell them all apart, but even here you might need the label to really tell the platinum from the gold if you don't have the best eyes.