Price Variations in Explorer 2 Rolex

[Brittain73]

Just curious as to why there are so many price variations in the explorer 2 model 16750. On ebay alone you see them go from anywhere around 3700 to 6000, same condition etc. I just don't understand why there is such a wide margin in prices where nothing on that particular model would make one more valuable than the other, right?? With the submariner for instance you see a much more tight knit grouping of prices as long as the model is the same and it falls within a certain time period, why is the explorer 2 an exception to this rule?

Best Brittain