You say it yourself: all the rows are blank for the variable. So what's to compare.
Copy the code generated by proc import that will be in the log. Paste into the editor and clean up. Change the informat to match that of the "date" variables you do see.
If you are reading multiple similar files then a data step is a much better way to go. That way you set all the properties for the variables and can make them the same for different data sets. Just change the name of the source file on the INFILE statement and the name of the output data set.
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