First-round WRs on Roster
The 49ers selected two of them, Crabtree and Jenkins. They acquired Ginn by trade and signed Moss as a free agent.
The thought hadn't occurred to me until Matt Maiocco of CSNBayArea.com pointed to what he considered the 49ers' unprecedented depth and talent at the position. There are still question marks at the position, but the talent is there.
A quick look at the NFL rosters I maintain for every team showed no team with as many first-round receivers on its roster.
Seattle has one (Mike Williams). The Rams have none.