Have you ever heard of a vehicle for the company owned 50% by the corporation and 50% personal?
No can't say that I have Sharon.
What I would normally see is a vehicle personally owned and used 50% for business ... whether the business is incorporated or not ... or a company owned vehicle that is used 50% for personal use. Neither of these are the same thing as co-ownership though.
If I were you, I'd look at license registration. It will tell you who the registered owner or owners is/are.