On a 40 year old game like L7, you know the flippers have been rebuilt dozens of times.
Operators may have used any flipper part that was rolling around in the bottom of their tool box, just to keep the game earning. Sometimes you find Bally parts, sometimes just scrap metal parts drilled out, or coil stops from a Gotlieb .
You should completely rebuild the flippers - everything.
That way, you don't have to worry about fixing one problem, only to have a mismatched orphaned part cause another problem a few weeks from now.
Now the best of all options, is to update to the unified base Williams flipper mechs.
These are the best, most responsive flipper mechs Williams ever made, and rebuild kits will only cost you $20 USD in the future.