I've made a few feet of this stuff.
when it was made the t&g was put through the machine finish face upwards.
You will need to check which way, if any, the board will "cup" or move to decide on the face side.
The solid profile cutters we used, machined the bottom edges of the T&G about 10 thou narrower, to ensure that the face edges butted up snugly and tight. check the cutters you will use making sure they are square to the spindle bed.
You may think about a couple of swipes with a nice sharp block plane, on the bottom edge!
The tongue and grooves were not central but thicker on the face side to allow re finishing, It may be a good idea to check on this should you be attempting a "match"
Central T&G,is a good idea, IMH as it will make life very much easier when trying do decide on a face edge.
HTH Regards Rodders