Alan has made a lot of changes to his books over the years so you can't take everything in your particular copy as face value. He used to have these changes listed on his WEB site, but for some reason it's no longer available. Hasn't been for several months now. I'm not sure why. Alan is a member of the CRG so perhaps he's in the process of changing hosts?
But anyway, the 163 manifold was used late in the 1968 model year starting I believe, sometime in March of 1968. (late in the 68 "Model" year, but early in the 68 "year"). My car has a 163 intake dated April 9th, 1968, but I've personally seen another 163 intake dated March 26th, 1968. The 069 manifold was discontinued at the same time the 163 was introduced, so there's some overlap that would have taken place for engines assembled in that time frame, but your June car would have come with the 163. But yes, do check the date code of your intake. I would be curious as to what it says.