woah charlie, not quite.
it depends on how the condition precedent was formed and worded. given the case, i'm afraid we don't have enough information on whether the condition was presented as a condition of contract, or a precedent. if the OP wants the car, he should argue that it was a condition. it would be in the seller's interest to argue that it was a precedent.
that said, yes you are correct that the invitation to treat doesn't confer a binding contract, but at the same time we can't say that a contract existed merely because of a given precedent (or even set of precedents). we simply don't have enough information about the process of events, nor the intention to create relations.
on a personal note, while many say that a verbal contract "is not worth the paper on which it's written", i always use such verbal agreements as a litmus test of the other party's intention and integrity. some weeks ago i found a suitable gtr - after lengthy discussion i agreed to buy the car, and the seller agreed to sell it to me. when i called back the next day to finalise bank cheque details, he said he'd already sold it. i saw this as an indicator of how he handled his transactions: if he was prepared to be fluid about the sale, what else (perhaps about the car itself) was he prepared to fudge?