Will there be different typesetting for ST 32-bit MCU body screen printing of the same model? Will there be different screen printing layouts due to different origin, packaging and environmental materials.

[一李.1]

The typesetting of the second picture is inconsistent with that of the datesheet, does it exist? In addition, what is the meaning of E3 and E4, and what is the meaning of "X"

[Tesla DeLorean]

printed or lasered?

Pure Tin (e3)

Rough Ni Pd AgAu (e4)

[一李.1]

Screen printing should be laser，Why are the typesetting of Screen printing for E4 and E3 different? The "X" in the left picture is behind the model, and the "2" in the right picture is behind the datecode. At the same time, the internal picture of the chip made of these two materials will be different when X-ray is taken, as shown in my following picture example。tks