While I’d rather go for the CAAD over the Allez, I’d be wary of a bike that has a mis-match of something major like Brifters or wheels, unless it’s at a very deep discount compared to similar bikes
Was the seller up front about the mis-match, or did you notice it and have to ask?
*I’ve sold a couple of ‘bitsa’ bikes before; to use up “it’s still good, but I’ll probably never use it on my bike parts;” but I’m very up-front about what it is, and I let it go cheap.