Pretty good numbers, probably the best for receptions and yards across first 50 games/first 3 seasons. Michael Thomas may have held the mark for most receptions in first 3 years - 321. Randy Moss probably held the record for most yards - 4163 - and most certainly for touchdowns - 43* - in first 3 years.
Receiving numbers are looking ridiculous over the past 20 years. I do wonder what some stars of yesteryear would do today.
Randy Moss had 47 total TDs - 43 receiving*, 3 rushing,1 punt return - over his first 3 years (48 games/43 starts). Note: 19% of his receptions were TDs.
Jerry Rice had 43 total TDs - 40 receiving, 3 rushing - over his first 3 years (44 games/31 starts - strike season his 3rd year). Note: 20% of his receptions were TDs; 22 receiving scores came in year 3... in 12 games.