Help me decode an intake manifold please

OK, I am looking for an intake manifold that will be date coded to my engine.
2205968 is correct for a 1962-67 383.
The problem I am having is for 67, the date codes are not the same as the later codes. The later codes appear to be in the normal date format, such as 6*9*69, (June 9, 1969).
For 67, the date codes have 2 numbers and a letter, the only letter I have seen is an X.

So, for example, what does this date code represent: 9X22

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Author: admin