Yes, Matt was sentenced 25 to life. But given the haniousness of his crime, it's probably safe to assume he would have never been paroled. He was a lifer IMO.
At the time Sweat murdered the cop, NYS did indeed have the death penalty. Because he did not want to risk a trial with the possibility of being sentenced to death, he agreed to plead guilty in order to receive a life sentence.
BBM
A history of capital punishment in NYS:
http://www.deathpenaltyinfo.org/new-york-1
"The death penalty has been abolished and reinstated several times in New York. New York's death penalty was accidentally abolished in 1860, when the legislature passed measures that repealed hanging as a method of execution but provided no other means of carrying out a death sentence. The mistake was corrected a year later in 1861.
Lewis E. Lawes, the warden of Sing Sing Prison from 1920-1941, advocated for the abolition of capital punishment. Although he supervised 303 executions, Lawes believed that capital punishment was inequitable and not a deterrent. He noted that barely 1 in 80 killers was executed, and said "Did you ever see a rich man go the whole route through to the Death House? I don’t know of any.”
In 1967, a compromise law was passed allowing for a very limited death penalty. In 1972, the U.S. Supreme Court invalidated all death penalty statutes in the country in Furman v. Georgia. The New York legislature rewrote the state's statute in 1973, providing for a mandatory death sentence for murdering a police officer, a correctional officer, or a murder in prison by an inmate serving a life sentence. In 1977, New York's high court effectively struck down the death penalty for the murder of a police officer or a correctional officer, and a 1984 ruling struck down capital punishment for murders committed by inmates serving life sentences, effectively abolishing New York's death penalty. From 1978 until 1994, measures repeatedly passed both houses of New York's state legislature that would have expanded or reinstated the death penalty, only to be vetoed by governors Hugh Carey and Mario Cuomo.
In 1995 newly-elected Governor George Pataki fulfilled a campaign promise and signed legislation reinstating the death penalty in New York, designating lethal injection as the new method of execution. In 2004, that statute was declared unconstitutional by the New York Court of Appeals, and in 2007 the last remaining death sentence was reduced to life, leaving New York with a vacant death row and no viable death penalty laws. In 2008 Governor David Paterson issued an executive order requiring the removal of all execution equipment from state facilities."
Pataki won the election based on his promise to reinstate the death penalty. Soon after
Pataki signed the legislation in '95, appeals were begun.
The mandate was put on hold.
Sweat murdered Broome County Sheriff's Deputy Kevin J. Tarsia on July 4, 2002.
Seven years into the appeals process. In reality, the death penalty was not in effect at the time of his pleading.
