Many manufacturers sell knives, but they sell at full retail so as not to compete with their dealers. So, citing manufacturer site is OK.
Citing a BF dealer member is OK too.
However, the discussion forums here are supposed to be all about the knives themselves, not where to buy them. So mostly we expect to see things like, "Hey I just got this new knife and it's really cool! Got it at [insert BF dealer member name here]. Let me tell you why I like the knife."
A Gold member can ask questions of valuation, but is subject to the same deal spotting rules as anyone else.