Transferring Title: Does Vehicle Owner Need to Update Title Before I Buy

My question involves vehicle registration or title in the state of: Missouri

Hello, I'm looking at purchasing a classic car as a project. The original owner (referred to as Owner A) died several years ago, and their estate went to auction. Owner B (current owner) purchased the vehicle in question at this time, obtaining
-The car & all parts
-A bill of sale
-A death certificate
-The original title, signed by executor of estate

However, Owner B never signed the title himself; his given reason is that the car was not in roadworthy condition, and he had been advised that registration and titling should be done together. I believe his excuse to be legitimate, i.e. he isn't trying to scam me.

I want to avoid any legal issues before I purchase the vehicle; is the only way to do this to get Owner B to update the title to himself (years after purchasing the vehicle from Owner A's estate) so he can legally transfer it to me? If so, is the best way to do that simply to bring all paperwork to the DMV (calling the DMV has not been useful)?

Transferring Title: Does Vehicle Owner Need to Update Title Before I Buy