A prototype of a source of polarized hydrogen and deuterium molecules has been developed at the Budker Institute of Nuclear Physics (BINP) in Novosibirsk. The Molecular Beam Source (MBS) is based on the Stern-Gerlach principle. First tests indicate that the separation of $\overrightarrow{H}_2$ and $\overrightarrow{D}_2$ molecules in the different nuclear spin projection states is possible. To verify this, a measurement of the nuclear spin polarization is needed. A Lamb-Shift Polarimeter (LSP) is well suited for this purpose. Therefore, an LSP has been built at the Institut für Kernphysik (IKP) of the Forschungszentrum Jülich. It has been shipped to Novosibirsk and there first successful tests were performed.