There are different pickups for different year ranges. One difference I'm seeing is the configuration of the plug on the end of the wire.

To answer your original question, no the pickup coil does not need replacing often. An ohmmeter should tell you if it's good. In your case either you've got a really crudded up wiring harness plug or a break in the signal wiring somewhere.

If there are only three pins in the connector you should be able to make a chart of the resistances between each pair of pins of a known good coil. Then you can test your "failed" coil and see if it matches.

I replaced a pickup coil on my old '64Dog because the original measured as "open" and I was getting no spark. After I bought and installed a new pickup coil assembly I measured the old one again and Miracle! it was OK. Corrosion in the socket was the culprit.

R.