Might be the first year of the EX?

Mine does have the "Made by Litespeed, Designed by Merckx" sticker on the seat tube (which is actually a tapered tube, not just ovalized).

I don't really know much more about these. Mine turned up in well-used condition in a distant rural location at a very low price, sold by an ex-Ironman competitor in his 70's who was also a former professional flat-track racer (BSA team).

Though very large for my size, the bike does exhibit perhaps the best steering behavior of any bike I've owned, under conditions of riding technical back roads at highest-possible speeds.
There is something about the steering that prevents anxiety, the ability to change direction instantly at will, but without any tendency toward a flighty steering feel.
It has an effortless, accurate, linear response that actually stands out from the others, yet stability and comfort are excellent.

Large picture here, hope this helps.