Not quite what I said. To clarify, Sprint is not putting backhaul on hold. They are speeding up NV site overhauls and allowing them to get ahead of the backhaul schedule. Backhaul is still proceeding per contract and will be connected after it's available at each completed NV site.
And you are correct, Sprint will not allow 4G LTE to be connected to legacy T1 backhaul. That would be a disaster.
Robert