I guess my Gravity Needs to be [386.08848 in/s^2]. I am still having COG problems, but will explain more in my next post.
Pound is not a mass, thus gravity is screwing up your calculation. Using SI units and a default mesh, SW Simulation got within 0.00024% of the mass calculated by SolidWorks (high precision). See attachments.
SolidWorks mass = 785.51669790 kg
SW Simulation mass = 7705.9 N / 9.81 m/s^2 = 785.51478084 kg
...up to 5 significant figures accurate, which is beyond the 4 sig figs given for the density.
This was done in SWS 2009 SP4.1.