Usually regsvr32 registers CLSID info in HKEY_LOCAL_MACHINE\software\Classes, so registration should be visible to all users.
The problem could be with your OCX. It might do something on start up that prevents to open it for non-admin users. For instance it requires to write something to HKEY_LOCAL_MACHINE registry, write to Windows directory, ...
You can check if this OCX is doing something for non-admin user by using Process Monitor tool and check for ACCESS_DENIED errors.
In case if your OCX doesn't do anything under admin account, what you can try to do is to register you OCX under HKEY_CURRENT_USER lever by using RegSvrEx tool. This way your OCX will be registered under current_user_level