Rarely but yes, a good example is the battle of Lang Vei in which the outpost south of Khe Sanh manned by elements of the 5th special forces group and indigenous forces allied to the US were attacked by NVA forces as prelude to the siege of Khe Sanh itself. The NVA sent in 2 armored companies composed of the amphibious PT-76 which took relatively heavy losses from US infantry anti-tank weapons but was successfully in overrunning the compound and achieving a tactical victory.