They're OK but they definitely should be lapped. The weight savings is so small, I would look to other opportunities to save weight.
The manufacturing process appears to start from an extrusion. The base is machined to fit individual receiver models. The rings are are left as extruded (not machined), however. Lapping shows they are not round. Using them without lapping will deform the scope tube, which could lead to a variety of problems.
Plus, if you later discover you have a boresight misalignment between the scope tube and rifle bore axes, you can't easily fix it using these rings. Standard dovetail and Weaver bases allow you to use Burris Signature rings to correct large boresight misalignment problems, or add elevation bias.