I don’t know if Trump was a democrat in ‘68 or not. Remember, at that time there still was a strong Republican presence in NYC and state. We had a Republican mayor and a Republican Governor. CT at that time was solid Republican.
Trump, according to this article, lived on the Upper East Side which was known as the Silk Stocking district. It remains a bit of a Republican stronghold to this very day. They did not vote for DeBlasio which is why he let them stew during a blizzard a year or so ago.
That “Republican” Mayor was the leftist Lindsay, who switched to the Democrats after the GOP dumped him from the ticket in 1969 for John Marchi. Ed Koch won the Silk Stocking district that year (’68) for the Democrats.
CT in 1968 had a Democrat Governor (John Dempsey), 2 Democrat Senators (Ribicoff & Tom Dodd) and Tom Meskill was the lone GOP officeholder in Congress (out of 8 members including the Senators). Far from solid GOP.