In MTC of 304L material it is mentioned that IGC Test as per ASTM A262 practice E is carried out and the material is passed the test. Why L grades are required to be IGC tested (Already this grade is having C<0.03% which means it will not sensitize) ?
Just to show that they didn't mess up the processing.
If you age for a long time it will effect the material, even with 0.015% C.
So if you under anneal the material it may re-sensitize easily.
And a comment, the MTR says practice E. This does not mean that they did the chemical test. The first part of "E" says to do the micro (practice A) and if it is OK then it passes. You can pass based on the micro, but not fail based on it.