Consensus here seems .. be wary of 2nd hand carbon fiber.. , in general
I'd say if its still in the bubble wrap, factory fresh , fine..

2nd hand You don't know it's use history if there were crashes, etc.

maybe like Aircraft, you count the hours of service, then replace it.

Madone is the only US made Trek frame, these days..
520's are going offshore ..

and their factory is in Wisconsin, so of course there is that too..
given Madison is the Capital of the state, and that is the CL you listed.