No. The 30 year rule (on the official secrets act) was supposed to offer up tentative clues on the matter and while, of course, not all was revealed there was very little to suggest he had any communist link. What it did reveal was preliminary talks with the US about 'statehood' (after our repeated rebuttals be the EEC) and some interesting insights into
In Place of Strife but nothing like that
EDIT: It also admonished Mrs T of the 'milk snatching' tag
Of course the stuff about her govt isn't due for another 2 years.