I don't know if a 80 TR7 would have vacuum advance or not; but certainly many Triumph engines of the smog era did not. Eliminating the vacuum advance reduced NOx emissions in the days before "3-way" catalysts.
My TR7 Haynes seems to imply that 1980 models still have vacuum retard, but no advance. But it's not very explicit on the topic, and certainly could be wrong.
Sorry, not much help, but it's all I got.