Date formatting

Hi - i was suprised that LT flagged the following months of dates in sentences as below. Is this the expected behavior ? Other three character months worked fine, but Sep and Mar were flagged. Is there a way to add this type of date formatting to LT ?
-thanks!

It was Sep 12, 2012.
category = 'Possible Typo’
fromx = 7
tox = 10
locqualityissuetype = 'misspelling’
msg = 'Possible spelling mistake found’
ruleid=‘MORFOLOGIK_RULE_EN_US’

It was Mar 12, 2012.
category = 'Grammer’
fromx = 7
tox = 10
locqualityissuetype = 'grammer’
msg = 'Consider using a past participle here: \‘marred\’.'
ruleId = ‘BEEN_PART_AGREEMENT’

Site gives no error for Sep.
It also gives no error no matter what day of the week I add, indicating that LT simply does not support any date-format other than the one used in the demo-text. (not even rehashing that in reverse triggers the date-mismatch-warning)