From what I've been able to tell, TriStars are dated by the first 2 numbers in their serial number. So his would be a 1988 model, which would just be the "TriStar". Obviously it isn't the 2-speed model, but still a neat one. Far less common than the CXLs and onward are. Looks similar, but has a different motor, notice it's rated at 7.5 amp instead of the 8.7 of the more powerful motor.
It also isn't the 50th anniversary decal. That was reserved for the first model of the CXL that came out in 1990. It looks like it says "As New As Tomorrow" but the last word is blurry so you can't tell. Like Dave said, a sharper picture would be greatly appreciated.