It is true that a baby will have some antibody from the mom up to about 6 months, yes.
I totally understand that you want to protect your child, and in infancy, this is very important, yes.
But there is an interesting thing going on because parents now get that cold sores are “herpes” and so they are very careful about not infecting kids with cold sores. But that means that society is pushing the first infection with HSV 1 to sexual maturity when the kids begin to receive oral sex and they get it genitally for the first time. It’s really complicated, isn’t it?
But in infancy you definitely want to be careful about kissing kids on the lips if you have HSV 1 infection orally. Or letting others do the same.