Absolutely correct Mike. When you consider that lactate threshold is, as I understand it, only affected by training whereas Max VO2 can actually be improved by losing weight whether or not the loss occured as a result of training.
An even more important factor as far as the 800 is concerned is lactate tolerance just as in the 400. You have to learn to continue to run fast when swimming in lactic acid. Threshold training helps that point come later in the race and lactate tolerance helps you to operate (both metabolically and biomehcanically) once you are there.