Autonumbers appear in several ways: strings, ints (old method), and long ints (new method). We currently can't parse long ints. When long ints are implemented it may also be worth implementing an auto-number type that would disallow identical entries in the column.
Warhammer 2 has also been observed to contain optional ints. These should be implemented at the same time. Their format is a boolean followed by an integer. They have currently only been observed with true values for the boolean.
Diff:
Note that this might also affect EditSF, ie the new type might need to be added there as well.
These data types are now implemented in a branch as of [r1217].
Related
Commit: [r1217]