Yup, it is always a good idea to research the CEO/Founders of a company you are considering joining to see as much of their history as you can. And if you see that they sold their previous company at firesale prices ('or undisclosed amount, not material to the acquiring company') you know that they missed their execution target that time. So a conversation with them is in order.

I have declined a number of offers over the years when my research into the CEO showed they were not the people who could get a company over the finish line, and have generally been pretty accurate in the eventual fate of those companies. Correlation isn't causation, but the CEO is the biggest win/lose variable in the mix.