Hi you're right!
The following are the steps to get a working piCore installation that opens up in GUI with no need to log in:
After flashing it on a micro sd card and booting it for the first time (wait for the "keys to show up" then hit enter).
$filetool.sh -b
$sudo reboot
Installing the GUI and making the system open in GUI:
$tce-install -iw TC
Wait for it to install and then:
$sudo reboot
Voila, now you got the GUI open up automatically!
Hope that this can be of help for anyone.
Kind regards,
meo