The Time Lord wrote:It's not rare.
Matt wore navy blue 'houndstooth' skinny jeans through the series (or at least, they were navy blue in the first half), but because of the low lighting you can't really see it. It's really noticeable in filming photos of ToA - as is the lighter jacket this figure sports. So while his fez is from the second half of the series, his outfit is from the first half.
Hope this helps!
We just mean on the figures. Most have black trousers, but some of these have blue. I went to Asda today and all of their Fez Doctors had black trousers, maybe it was only in a couple of batches of figures?