yes, they do.
I just wanted to highlight, that a single LCG can be a pain in the ass for a medium tank. both fractions rely on a good combination of units.
Mammoth tanks only might work. but they might also end up blocking each other permanently, feeding Nod with easy VP.
Meds only might work, but they lack DPS/splash (they can't replace MRLS or Mammoth) - unless they move & FIRE as a group!
Artys only might work.... until GDI kills the field reps or gets 2 mammoth tanks, focusing each arty after the other [or GDI uses Gunner to counter Arties in the first place - see Islands.....]
LTs only might work - but they usually don't due to lack of DPS (Arties needed!).
literally anything might work. but a balanced combination of various units has much better chances to succeed.