Anquan Boldin is a lock. So is Jon Baldwin, acquired this week from the Kansas City Chiefs for A.J. Jenkins.But who else will be among the 49ers receiving corps when the team sets its 53-man roster before the season opener against Green Bay on Sept. 8?It's likely that head coach Jim Harbaugh will carry six wide receivers on his roster. If Boldin is one and Baldwin is two, then Kyle Williams – back and healthy from injury – appears to be No. 3 and free-agent pickup Marlon Moore is No. 4. Harbaugh last week indicated Williams and Moore are on target to make the roster.Moore, the former Dolphin, has been one of the team's best receivers in camp and also has a history of fine play on special teams."Kyle Williams, Marlon Moore have a bit of a head start in that regard," Harbaugh told reporters, when asked about the likely Game 1 starter opposite Boldin.That leaves a competition between rookie Quinton Patton, veteran Kassim Osgood (also an outstanding special teams player), former Colts standout Austin Collie, Lavelle Hawkins, Chad Hall, Ricardo Lockette and Chuck Jacobs for the final two jobs.This week, Harbaugh indicated that he hopes to give those players on the bubble a...