I am assuming you mean camping platforms when you posted the question, "Does Lake Taghkanic state Park have decks?" I worked there for 6 summers and as of the late 1980's yes, they had campsites with and without platforms. You need to request such when you are obtaining your campsite at the park office.
Lake Kegonsa State Park was created in 1962.
Lake Scott State Park was created in 1928.
Lake Wissota State Park was created in 1961.
Lake Anna State Park was created in 1983.
Moncove Lake State Park was created in 1990.
Nolin Lake State Park was created in 2001.
Lake D'Arbonne State Park was created in 1967.
Moose Lake State Park was created in 1971.
Trinidad Lake State Park was created in 1980.
Kincaid Lake State Park was created in 1963.
Morphy Lake State Park was created in 1965.
Grayson Lake State Park was created in 1970.