This observation is based on my sense perception that in initial images of 67P's rubber duck shape, it looked to me short with a fat neck. This is one of the earliest images from the sun side approach in August 2014.
Since then there hasn't been many sun side images at roughly the same angle, but the near 180 degree phase sojourn in 2016 showed the 67P duck shape silhouetted. It looked to me a little more drawn out, and the neck not quite as wide.
I have taken measurements with a ruler on an iPad and the ratios do seem to match my perception. However, this is just the sort of thing that requires scientific rigour to confirm. This rough and ready measurement is, I believe, enough to spark a detailed investigation into whether this is a real phenomenon or not. It just requires calculations of the length of the nucleus and the neck width from 2014 data and 2016 data.