What is the year of a 3 digit serial number on a 1941 luger?

Not sure I understand your question. A 1941 Luger would have been made in 1941, of course. The vast majority of the pistols were stamped with a four-digit serial number. This number cycle was repeated monthly by the various arsenals, thus making it possible to have between 250 and 300 pistols bearing the same serial number. Distinguishing factors making the identification of each pistol unique are the alpha letter appearing beneath or following the serial number; the year of manufacture; and the individual arsenal/code markings on each pistol. The serial number, always stamped on the frame, may also appear on the receiver and barrel. If the serial numbers don't match, this indicates the pistol was assembled from parts of several pistols.