Try it and see!

  192.168.1.1$ ip link set sit0 up
  192.168.1.2$ ip link set sit0 up
  192.168.1.2$ ping ::192.168.1.1
  64 bytes from ::192.168.1.1: icmp_seq=1 ttl=64 time=0.812 ms

(It works over the Internet too, though make sure your firewall doesn't block protocol 41 and that the packet doesn't get NATed.)

Notice how this doesn't really help you at all. You still need a functional v4 network, you still need v6 support in the kernel on both sides and your programs still need to support AF_INET6 sockets -- at which point, why not just use ::ffff:192.168.1.1 which sends packets without the tunnelling and doesn't need OS support on the far side, or 192.168.1.1 which works with AF_INET sockets and doesn't need tunnelling or any OS support on either side? This is strictly worse than the former option and less compatible than the second.