When did Strats get a 5 way switch?
Fender introduced a five-way selector in 1977, making such pickup combinations more stable.
Is a 5 way switch common?
The 5-way Strat switch is the most common switch you'll find in Stratocaster guitars. The original Stratocaster had a 3-way switch (same as a Tele) to select one of three pickups. But over time players noticed an interesting sound when switching from one pickup to the next.