The Dairylea games were on specific dates, usually weeknights & were usually in the outfield upper deck. There were 5,000 seats available to Dairylea on those dates. I know one lucky Mets fan, "the Don" Joe, who said his Dairylea coupons got him in the last row of seats on what turned out to be Willie Mays Night at Shea.
Dairylea would go to sponsor photo album promotion days starting in the 1974 season & lasting a few years. Their logo was featured on many Mets schedules, scorecards & yearbooks throughout the seventies.
The Dairylea Company was founded back in 1907 in Orange County, New York. They eventually formed a business co-operative in the early 1920's & began using trucks to deliver milk in a time when the railway dominated the market.
In the 1950's they used Televisions cowboy Hopalong Cassidy as its top promoter & hired one of the first women to be on a board of directors. In 1965 they revolutionized the industry opening an automated milk plant in Goshen, New York.