Except it didn't. In 1959, when
SME introduced a
3009 series of tonearms, this style of headshell was already in use. One year earlier, Ortofon introduced its
SPU series of pickups, mounted in a short (A) and long (G) headshells to fit Ortofon's own tonearms. To prevent people from sticking an A headshell into a tonearm designed for G and vice versa, Ortofon gave them incompatible connectors. A's barrel had a locking pin at the bottom, and G's at the top.
SME 3009, with its sliding base, could accommodate both. So SME used a female headshell connector with two slots, top and bottom.