Yes MSEP goes back to 1977, Spectro only 1991.
It anything should be playing for the 40th it should be MSEP.
Its like when people want CoP to go back to the original sound track of "Now is the Time" from the GE years not realizing that "Great Big Beautiful Tomorrow" is the original song and "Now is the Time" was an ad to sell appliances.
Its just what you grew up with, I have only seen MSEP (1977 as a teenager, 1999 with my family and 2011 again with my family) so thats my night time parade that I grew up with.