I suspect the answer is NO, and you'll end up with a bit of dutch roll during cruise, very much doubt the amplitude would be doubled.
I'm sure I've flown the 747 with an unserviceable yaw damper system, and more than once. Absolutely no evidence of Dutch Roll in the cruise. The yaw damper system makes co-ordinated turns more elegant and comfortable, but it is not a Dutch roll-prone aeroplane. The VC10 could do some amazing DRs, with the whole tailplane violently waggling- it was quite surreal observing the tail through the aft overhead periscope.