Well, yeah, expectations do matter. And at this stage I definitely wouldn't be able to tell in a blind test whether a given tea was from a spring or autumn harvest. The "general consensus" seems to be that autumn tea from a given area is usually not as good as spring tea from the same area, and even if this is often the case there will of course be a number of autumn teas that are still very good (and better than a lot of spring teas), but it might (as you suggest) color how people actually approach these teas and create self-fulfilling prophesies of sort.
So yeah, there is the expectation factor, which may or may not be huge. But in other cases where I have expected that I will like one tea more than another (because, say, it's more expensive, or it's generally been receiving more positive reviews) I found that my taste buds prove my initial assumptions wrong many times. (Since I have a pretty horrendous memory I almost always forget which one of my samples were most expensive and usually don't check until after I've tasted the tea.) In this case too, I expected to like the TU tea as it received good reviews from a number of people (
including MarshalN), but in the end found it a lot less interesting than any other tea I've tried from the same price range (the GFZ sells for $97 a cake, the Yiwu from pu-erh.sk is around the same price per gram).
This is not meant as a critique of either vendor, I've liked almost everything I've received from both (and will definitely order more from them in the future), and I am too inexperienced to make any sort of useful comment regarding whether or not these two teas are "typical autumn teas" or if such categorization even makes sense...