Sorry, I mean 'soldering' and nothing else..

No Commodore did not. It's the infamous "piggyback" memory upgrade that was presented in an article in the magazine "Amazing Computing" issue number 1, volume 2 from 1987.

By molding two memory IC's together on top of the memory IC's on the motherboard you could upgrade it to 1mb ram! Those wires are needed to recognise the extra memory.

It was a DIY project that voided the guarantiee for sure! ;)