A few days after asking the weight, my lbs got two of the 4.5's. We looked at the 56cm with a compact.
We put it on a Park DS-1 digital scale and found the grand total was....
19.07
This does include reflectors and plastic platform pedals from a test ride.
I think for giggles, I'll go back and get the weight on a 5.1 & 5.2 they have.