I guess that depends on the meaning of "very little armor" and the field of fire of your particular foxhole.
The United States Army used an entire Armored Cavlary Regiment and several mechanized brigades that included at least one tank battalion each with M48 tanks. Divisional Cavalry Squadrons had M551 Sheridans and some used M48's. The Marines also used M-48s and the ARVN used M-47's quite effectively.
Most commanders would have liked to have had more Armor, but the staff wizards at the Pentagon didn't think that they were suitable. Operations in many areas proven them wrong and in some places they were essential to maintaining lines of communication. But, of course, Vietnam wasn't an insurgency. It was a war against the Regular Army of North Vietnam augmented by regular force of the Viet Cong and supported by insurgent auxiliaries. The insurgents were largely destroyed by 1968 and in 1975, South Vietnam fell to a conventional attack by North Vietnamese Armored Columns. Some of us remember those "insurgent" tanks.
I drove Hwy 1 from Dong Ba Thin(N) and out Hwy 2 nearly to
Laos(W) (Camp Townes),,,”Evil Eye”,,,8/26 Arty,,,
We had “Dusters” at Town Town,,,
They were the only thing with tracks-n-gunz that I saw,,,
That armor must have been south of me...