Rccardr - thank you.
P4X Z5140: This model is Pro SLX (the name Corsa Extra didn't exist yet), produced at the turn of 85/86, and the Lotto team was riding very similar bikes in 1986. The letter P was inverted or lying down so as not to be confused with the poorly marked letter R, which always meant Reynolds 531.
The Z series covers production from late summer 1984 to autumn 1986.
ultraman6970:
"Sam" did not paint frames, he was responsible for removing the imperfections and carefully "smoothing" the frames before painting (in the "white" catalogue there is a photo on which 4 men are shown in this particular work). Series and numbers do not have any reference to specific dates, it is simply a sequence of markings (the serial number includes a letter and digits - together). The rest of the decryption - flawless
Corsa Extra - 1988, Corsa - autumn 1990.