We already knew Brown was in the Bay Area because he plans to work out with Hall of Fame wide receiver Jerry Rice on Tuesday, including running "The Hill."
Brown (6-0, 226) also met with the 49ers at the NFL Scouting Combine in February. He set a school record for receiving yards in a single game (233) during the first game of his sophomore year in 2017 and finished each of his final two seasons with the Rebels surpassing 1,200 receiving yards.
Brown led the team in receiving as a junior in 2018 and finished the year with 85 receptions for 1,320 yards with six touchdowns. He was named first-team All-SEC for the second consecutive year.
Samuel (5-11, 214) had 62 receptions for 882 yards (14.2-yard average) with 11 touchdowns as a senior with the Gamecocks in 2018. He participated in the Senior Bowl in January and was part of the South squad coached by 49ers head coach Kyle Shanahan and his staff.
Samuel also met with San Francisco in February at the NFL Scouting Combine.
The 49ers also hosted former Arizona State wide receiver N'Keal Harry for a pre-draft visit on Monday.