Sorry, but that is a broken stamp. The middle number is a 6. Note that the lower part of the "L" in CAL is also broken.
FWIW, I recommend that the rifle not be fired. Even the 7.62 NATO milstandard pressure of 52,000 psi is quite a bit higher than the 40,000 psi the rifle was designed for.
Ron, the French Gendarmerie, the Spanish Guardia Civil and the Italian Carabinieri are examples of national police forces that are actually part of the nation's armed forces. The members are trained as soldiers, in regular army training camps, then choose to go into the national police rather than the regular army. They normally wear police uniforms and carry only light weapons, but they have or can obtain military weapons and equipment if necessary.
Those nations also have separate city/local police who are closer to what we think of as police forces.
(Edited to correct "surete" to "gendarmerie".)
Jim