Hi Instow,

The Lisa 1 had two notoriously unreliable "Twiggy" disk drives, yes. The upgrade from 1 to 2 involved a replacement front panel, different floppy drive case and drives, and slight modifications made to the I/O board. There wouldn't be any evidence other than the serial number if yours had been upgraded. 

If you'd like some more help getting your Lisa up and running, shoot me a private message...

-fri0701