Generally, in the case of mass productions guns, advertised weights can't really be accepted at face value. You may agree that factors such as wood density etc will almost always bring to surface some differences.
CZ shotguns aren't much different in that aspect. However, their advertised figures are mostly quite close except for the 16ga side-by-sides (both Bobwhite and Ringneck models).....where those models are around the 7+lbs range as opposed to what is printed on the website.