On hyperphysics the hyperfine structure of hydrogen is compared to that of deuterium:
According the Hyperfine structure on Wikipedia
In atoms, hyperfine structure arises from the energy of the nuclear magnetic dipole moment interacting with the magnetic field generated by the electrons and the energy of the nuclear electric quadrupole moment in the electric field gradient due to the distribution of charge within the atom.
For atomic hydrogen the distribution of the magnetic dipole of the proton and of the electron seems to me to be unambiguous and the two lines of the hyperfine structure are from the Spin isomers of hydrogen molecules.
Comes the hydrogen hyperfine structure from H2-molecule, interacting H-atoms or independent H-atoms?