Hello German folks :-)

[CTHTC]

0

is it this command, which sets product code to 059X4V9

Yes

The only difference is, that phone shows LTE on screen now. But my old Lumia 930 shows just L on screen.

Thats ok. i have the same differenz by my Lumia 1520 and Lumia 950XL.

So I was thinking about flashing the device once more, but with 059X5B6 firmware now :-)

Of course.
You can also test:
thor2 -mode uefiflash -ffufile "RM1104_neu.ffu" -productcodeupdate 059X5B6 -skip_flash