The second generation of the "Ref. 5270", the "Ref. 5270G-014 (blue dial)", has a bulging calendar at the 6 o'clock position and a tachymeter on the outer periphery that bulges downward at the 6 o'clock position.
This second generation was actually produced for a short period of just one year.
This is an unused item that has never been worn since purchase.
The "Ref. 5270" series has been less available recently, and the price seems to have gone up compared to before.
It is very difficult to find one in this condition, so we recommend this opportunity to anyone looking.