I did that when I purchased my used Toyota a few years ago. I told the dealer to hold the car until I could get a bank check issued by my credit union (no physical branches in my state so I had to call during business hours) and he said I could drive off that day. I was surprised but he just printed a temporary registration and a week later I drove by to finalize the paperwork after the check arrived.

It was a small dealership started by some ex-Microsoft guys and I was working at Microsoft at the time which might have had something to do with it, but it wasn’t like they verified my employment or anything. I assume they felt safe doing that considering the alternative would have been a career ending grand theft auto charge.