I, too, have seen this Trump aircraft at LaGuardia. It is usually parked to the north of the Delta Shuttle terminal. To my knowledge, it was never operated on the Trump Shuttle, because all Trump Shuttle aircraft were taken over by the USAir Shuttle. I have even seen this aircraft during the Trump Shuttle days, and if I remember correctly, the registration number did not have the TS suffix. I remember reading in an old Airliners or Airways magazine that it was Donald Trump's private aircraft. I wish these magazines were indexed, since I have every issue ever published, but I just don't have the time right now to search through all of them to find the article.
Fly Eastern's Golden Falcon DC-7B