That probably has more to do with the pricing itself, as opposed to being a bellwether for forum sales.
Sometimes yes, sometimes no.
I buy and sell a lot of GA where pricing baselines are either: (i) minimal and unreliable; or (ii) non-existent. Therefore, the ask price is a starting point for discussions. However, when there is plenty of sales data I tend to price on the low end. There is a unique sales culture here that is hard to predict. Books that sell near-instantly on ebay, for example, sit untouched here at below-market prices. The opposite is also true where very high priced books move rapidly here but sit on dealer sites with nary a look.