Fruits might be fewer or smaller but you never know.. If it were me, I'd try to keep it going and try to produce pure seeds from that plant. I live in zone 10a and I'd never had ANY annual squash survive winter. I grew cabocha last year and it was the first to run out of steam and die before winter even came. You might have something special... I'd just plant more cabocha just in case that plant fails to produce.

There ARE perennial squash and Ive heard that some grown as annuals can survive as perennials in warmer climates. I know I've seen sponge gourds survive year around in warmer climates.

Interestingly the 2 fruits it produced last yr had "ripened" and showed tinge of orange when I cut them off the vine but the seeds were all "empty" as if they were all seed coat and no inside germ. I thought it just didn't have enough time to mature before the cold forced it to "ripen."
I'll try to push it this year and see if it will fare any better.

the kabocha that survived winter is now with a single fruit. I hope it ripens in time.