Not likely to be legit. If I were to have an interest in having someone buy my company (actually, I no longer own one), then I would not trust any source that I did not find on my own. If they sent you a message, they sent the same message to ten million others, without bothering to check if you really had a company in the first place. It is like getting the phone call that said they have been working in my neighborhood and would like to redo my windows.