The history is way off here, Silk Road was one of the first two completely public darknet markets (the other being the short-lived Open Vendor Database) but there were private darknet markets long before, e.g. The Farmer's Market.
> Use of the Internet to facilitate the marketing and sales of physical goods - drugs, weapons, false identification papers - began latest in the late 1990s, but usually focused on local geographic markets in major cities. This was due to the fact that payment and delivery still required in person meetings.
Not so, back then and still to this day drug dealers simply throw a stack of cash in the mail. The clearnet markets for "research chemicals" all operated this way and went basically unchecked until Operation Web Tryp in 2004, which began an era of harsher enforcement of the Federal Analogue Act.