Waiting on weighty matters
Ken,
As anyone who has operated converted aircraft will know, there are many variables. The original configuration and mods to include structural modifications due to ADs, SBs or structural repair. The mods involved in the STC to create, strengthen the flooring, cut and reinforce the fuselage, install the door and cargo handling equipment.
In short there is NO exact standard aircraft empty weight. The max TO weights, Zero Fuel Weights, and max Landing weights can vary as well. You will need to get the data from the aircraft certification data sheet or the weight and balance data for the specific numbers.
Sorry about that, but that is the curse of converted aircraft. Even with a standardized fleet, over time, the values will diverge due to repairs and modifications that may be unique to a particular fuselage. Air stairs and cargo handling equipment are hard on aircraft!