Fewer yards due to fewer touches. However, the chance at 13 games instead of 11 would equalize it some.
ISU ran 763 offensive plays in Troy's junior year -- 524 rush (402 by Troy) and 239 pass.
This year, to compare: 837 plays (385 rush, 452 pass)
1996: 69.4 plays per game
2019: 69.7 plays per game
So the number of plays is a wash
1996: 47.6 rush attempts per game (36.5 by Troy)
2019: 32.1 rush attempts per game
Troy averaged more carries per game than ISU does now as a team
Assume he still gets the same 5.4 ypc, but averages 25 carries in the modern offense.
25 carries * 5.4 ypc * 12 games = 1,620 yards
That would put him right around 5th in FBS this year
For comparison, Chuba Hubbard is averaging 25.75 carries per game, but at over 6.2 ypc.