Yes, ILBs are MLBs.
Here are some tackle-not-sacks LBs with 150+ tackles since 2005 (p5):
Luke Kuechley, BC (thrice 150+)
Evan Weaver, Cal (twice 150+)
Ben Burr-Kirven, UW
Jay Higgins, IA
Scooby Wright, ARI (+14 sacks, dude was on crack)
Mason Foster, UW
Jordon Dizon, CU
Abdul Hodge, IA
Curtis Lofton, OU
Chad Greenway, IA
Tim McGarigle, NW
Kenneth Murray, OU
Sean Weatherspoon, MIZ
Alvin Bowen, ISU
Greg Jones, MSU
Dele Harding, ILL
Kentrell Brothers, MIZ
Lavonte David, UNL
J Leman, ILL
Scott McKillop, PIT
Eric Kendricks, UCLA (150 & 149)
Mike Taylor, WIS
.
So, as most of us know, this list is funny, because all the all-time tackles leaders were in the 70s, when teams ran the ball 80% of the time. But these are the modern guys. I only know of some of them.