I don't know which optional tanks it had. Given the winglets are Aviation Enterprises maybe the fuel cells are also. I know that some of the optional tip tanks do have a jetison system so that if you have to land before exhausting the fuel the fuel can be dumped so that the gross weight is legal for landing. The increased gross weight is for T/O and flight only and not landing.
Here is the info on the Flint extended tip tanks. It increases the Gross Wgt to 4,630 except where the GW is already 4,700 from Cessna. No dump system on the Flint Kit.
http://www.flintaero.com/337.htm