They certainly did do retrofits. I don't know if they still do. But if you think you will get nice bright and shiny IPv6 with your bright and shiny new Gigabit-capable network, you'll need to think again*. No IPv6, and they use Carrier-Grade NAT. This takes the shine off things a bit.
*Apparently, it is finally being rolled out, but it hasn't reached the routers I am responsible for.