They could possibly zero pad old IPs.
Example: IPv4 - 255.255.255.255 would become 0.0.0.0.0.0.0.0.0.0.0.0.255.2 55.255.255 for IPv6.
Not quite, each block in an IPv4 address is 1 byte, or 8 bits. 32 bits to represent the whole address.
IPv6 is 128-bit, which is 16 bits split over 8 fields. It would look more like this:
0.0.0.0.255.255.255.255
(each block can be a number from 0-65536)
You're generally comparing apples to oranges by doing this, however.