Can you folks tell me what to look for in a cutaway Curta that was done by Contina? How can I tell the difference between a factory cutaway and a “fake” cutaway?

I would not call the non-Contina cut models fakes - usually they are very professionally made.
As documentation, there are only some index cards of Contina AG. - these cut models can be safely referred to.





All cutaway models in the green box are logically also genuine. Beyond that, nothing is known.
An (almost) certain assignment to the Contina origin can be made on the basis of the serial number and the type of cuts. Alos the origin of such a Curta would help.

Is there a particular Curta for which you would like an estimate? Pictures and the serial number would be helpful....

I recently came across a type 1 on an auction site that was cut apart. But it wasn’t in a display case or anything like that. The auction is over now and I didn’t bid but here is the listing anyway….

https://www.liveauctioneers.com/item/124330613_curta-type-i-calculator-system-curt-kerzstark-made-in-liechtenstein-by-contina-ag-mauren-type-i