Seems like it, either that or it's something else, maybe the people he believes could kill him, because Shanks only became an emperor 6 years ago, with the only known encounter between them(during MF) ending with Shanks coming clean, not suggesting there to have been a huge fight.
But it's possible that in the short encounter, Shanks injured him heavily(Kaido usually doesn't care about getting tagged at the beginning of battle, counting on his durability) and thus with that encounter making him realize that Shanks is among the people who could kill him.
That's why I'm even more wondering about their encounter during MF.
Knowing Oda, as Luffy's idol, with Shanks claiming before the arc that Luffy might be close to meet, he'd probably use that encounter to hype Shanks