Can an apt offer a 6 month lease, but then write up lease for 7 months without disclosing this to the tenant?

Moved into an apt on 4/1/06 with a 6 month lease. Now want to move out at end of lease and mgr said I signed lease for 7 months. This was never disclosed to me and I didn't catch the 7 month timeframe written on the lease. Is this legal to write up a lease for a different timeframe than verbally agreed upon?