I would say yes although I usually just use the install kernel (bare.i).
The reason I say yes is that I have done complete install from hard drive using the cd for boot and starting/running the instal program. I put the directory /slackware on the partition that would become /home after the install.
If the choose kerenel section of the install also let's you select the hard drive as installation media, than your on.
If not, and the kernel is too big for a floppy, and you don't want to burn to a cd, it's a small matter to copy the kernel, ./config file and system map to /boot after the install and redirect your lilo or grub accordingly.