TSO C129 and 145/146 certified receivers must have an automatic RAIM prediction service prior to passing the FAF.
They must not enter Approach mode if the prediction fails, or if in any event RAIM is not available at the FAF.
If a receiver doesn't do those things without pilot input, it's not suitable for IFR use.
This information is found in the FAA's TSO archive.
As wishiwasupthere says, a paper NOTAM prediction is superior.
Apparently there are some ATOs who mandate a manual RAIM prediction in flight. It's good airmanship to know how to do this, but in most cases there is no legal requirement to do so.