Played a friend's all-original '67 FG 4005 today. The bridge pickup sounded, as expected, very thin and weak. A .0047mF cap on a pickup so close to the bridge is lethal.
So I suggested shunting it. Five minutes later we plugged her in. Wow!!! HELLO bridge pickup! Where have you been hiding in the last 47 years?!
The bass sounds soooo much better now both in the bridge position (previously totally useless) and with both pickups on.
Bypassing the cap in a 4005 is much more dramatic than in a 4001/pre-'85 4003.