Help evaluating Polerouter Date

Alright, I am bumping this thread to ask some questions about a ref 204503/3 that I now own. It's actually a different watch than the one listed in the OP.

First question - mine has a signed crystal with trapezoidal loupe (assuming that it's original since it's signed). Someone made a comment above that this reference should have a round loupe. Have you all seen both?

Second question - the reference tables state that the lug width should be 19mm. I measured both sides of the case with a caliper and come to about 18.40-18.45mm (pics below). I've measured many times and am confident the measurement is correct. Any comment on this?

Quite unusual - mine are 18.9-19.0.
Perhaps it's an early/late serial thing?
Batches of cases could have some slight differences - I've noticed a similar thing on the very early serial 204610 which seem to have a thinner lug width than the later serials.