Is there a wire difference between 24 Mbps and 45 Mbps from curb to house?

I'm scheduled for a triple pack u-verse (U300) install. I asked for 24 Mbps internet speed, but I think I want to upgrade to 45 Mbps speed. I have not had regular phone service for a couple of years. I'm not sure if it is still operational. Do both of these speeds utilize the same wire to the NID? Or will they have to run another? -- I need speed...