from B449-93, Table 1 Classification of Chromate Coatings. Class 3 appearance is colorless. Yes, it is a chromate. All coatings in B449-93 are chromate or mixed chromate-phosphate.
It may be of interest that the salt spray requirements for some alloys (heat treatable & castings) are less than for MIL-C-5541E, Class 3.
