hy-brasil,
the proofs also have the lines at the left and even at the right of the head:
https://siegelauctions.com/lot_grd....emailflag=onactually, all recently sold 205 and 205C have those lines, so it seems to be just normal.
205C
https://siegelauctions.com/lot_grd....emailflag=on205
https://siegelauctions.com/lot_grd....emailflag=onI didn't think it was something worth think about and didn't do any speculation about the special printing, but just wanted to chime in as it was mentioned that there were no diagonal lines at all. So hy-brasil, I guess you will find them also in your stamps with a good magnification.