Great Deal? Dupla CO2-set Delta for $55?

Well folks the subject says it all.
I have the chance to get the Dupla CO2-set Delta for $55, should I do it?  It
comes with a 12oz CO2 bottle, a pressure reducer, a diffusoir, and a little
CO2 test kit thingy.  I would want to get a bigger CO2 bottle, so does
anybody know if the regulator would fit on another bigger bottle?

     - Keith