I don't think the Happ stick above will fit Encryptor's restrictor repro. They're made to fit in the older base assemblies made by Midway. You'll have to find a used one. Luckily, (as mentioned above) they're built tough, so there's nothing wrong with a used one. Plus, used is a ton cheaper.
*edit- Just went and had a look at the diagram on the Happ site. They might fit after all.