If you gave birth in the hospital, then it is a near certainty that your baby did receive the injection--unless you specifically waived it. Yeah, you have to find those records, wherever you gave birth.
However, Vit K does not prevent ALL cases of Hemmorhagic Disease of Newborns (HDN...otherwise known as Vit K Deficiency Bleeding/VKDB). Research I've read indicates that Vit K seems to prevent about 1/2 or a bit more cases of HDN--but not all cases of newborn hemmorhaging are caused by Vit K deficiency (no one knows what else may cause it). Hence, Vit K cannot help all babies.