It'll be the version that is required by the contract, and if that contract is in dispute then what the court decides. If the contract states that you must tell them if you remove airbags, fine. If they specifically ask you on the phone if you've removed an airbag, fine. If the contract asks you to declare any modifications and you declare that you have removed an OEM wheel and replaced it with a Sparco Go-Faster 3000, then that also satisfies the requirements. There's no shades of grey about that, it's fact.
If you just say "Oh, er, it's a black one" or "Erm, a Sparco one" then yeah, ambiguity creeps in. However, if the insurer is happy with the answer you give them, then why give them extra details they don't need? Put it this way, in what way do you think I've lied or not declared? In what way would a court find in favour of the insurer?
Another example (and I know you'll hate this one!), on my current car I have detailed as modifications 'exhaust changes' and 'suspension changes'. Their wording, not mine: I told them what I'd done, but that was how they chose to write it on the policy. Makes sense to both parties.