i was dumping photos off my camera this morning, so i took a quick shot of a prewar pickup...
i popped off the front shoe which took about 5 seconds. with the pickup off, you can see the fixed copper strip which bends up to form a spring keeping the floating shoe on track. this piece sometimes breaks off which is what i was referring to. as you can see with the rear pickup, these shoes do wear over time.
again, good luck...gary