Seams and roundoff error?

I decided to check some of the texture coordinates for the opposite seam directly and see if they mapped to Frank. Some did, some did not. Then moved around the tex coords that mapped to black around by 1 pixel and found that they started mapping to Frank.

This lead to the realization that I was using GL_NEAREST for the texture filtering and not GL_LINEAR. Switching to GL_LINEAR gives the following:This still isn't what I'd expect to see, but at least I know that my seam finding algorithm is probably working correctly.