On top of your speedo being off, the Cruze does have a different bolt pattern(5X105) Isn't the Cobalt 4 lug pattern? They will not work.
FWIW, I have a 4 bolt Cobalt. but there are also 5 bolt ones.Both are 5 bolt, but I figured there would be issues. Never even thought of the actual age themselves. Quick google search confirmed, thanks