I know that later volumes of the internationals (starting with I believe the volumes for 1971-1973) do carry the Scott numbers printed in the spaces, but the earlier volumes do not, or at least they didn't in the 1990s when I was buying my sets. In the end I just wrote the numbers in lightly with pencil (as I was using Scott mounts for the stamps that didn't cause risk to stamps picking up any residue from the pencil lead). New printings of the earlier volumes may have indeed added them in, but if you got a used one, then putting the info in yourself is prob the best solution if you are using mounts.
Otherwise, there is always the Big Blue Key to internaional volume 1 that one can refer to. http://bigblue1840-1940.blogspot.co...mpleted.html