I don't imagine it being a big difference. Spidertrax lists their 3" OD, 1/4" wall housing at 70 lbs. Stepping up to 3/8" wall (not needed in a strip truck IMO) puts it up to 80 lbs. It's been a couple years since I handled a bare OEM housing, but I remember it being 40-50 lbs.
A Fabbed housing can be built with Chromoly Plate and Axle tubes vs. a stamped steel one.Plus the fabbed one will end up stronger due to more bracing..........