Bahrain Visa

Is an expat from saudi holding an iqama which indicated with "labor" or "worker" as its label will be guaranteed to enter the kingdom of bahrain by getting visa on arrival? or through online only? Thank you

Nothing is guaranteed. There should be no issue if your nationality isn't Pakistan or Bangladesh as these are the ones who are usually denied on low professions.

He is a filipino actually and he was just not sure about it.

As mentioned above by XTang, no one can say for sure. He just has to try.