A date of 1937 means there's a chance it is connected to the second world war. Love tokens had been out of fashion for many decades. The letters are deep struck, professionally made but aligned by hand.
Pure conjecture with the few facts available, I would say the counterpuncher was someone who went through the first world war (think of sergeant Wilson from dad's army) and thought it wise to take precautions at work. Maybe the S stands for school and our counterpuncher was a teacher at a technical school who was afraid there would be a shortage of coins?
Peter
