It depends where your ancestors lived and how remote they were from the enumerator's base of operation. It is not unusual to find population schedules taken in those months, since the Bureau of the Census reports:
"The seventh census was governed by the provisions of an act of May 23, 1850, which directed that six schedules be used to collect the information requested by the Congress. The enumeration began on June1, 1850, and was to be completed, with the results returned to the Secretary of the Interior by November 1, 1850."