Totally correct.
1st tour, we were doing S and D and RoadRunners against VC only, with occasional PAVN advisors.
2d tour, it was all PAVN with Sov and PLA advisors. They even brought PT-76 and later T54/55 south.
I knew an SF SSG who came north to Northern I Corp and was attached to the 75th Rangers with the 1st Bde, 5th Mech Inf Div. He told me unclassified stuff about SFD B-50 working out of Nha Trang’s Project Omega. He mentioned the Road Runner Teams there. Were you with that outfit?
I knew they had PT-76 at Ben Het in 69, and the 69th Armor knocked out a couple of them. They had us doing more frequent coincidence range finder and fire control system checks and loading a bit more HEAT in our basic load in anticipation of anti-armor encounters. But I was unaware of T54/55’s over the border untill the spring of ‘72 and their victorious offensive in 75. Where did they bring up the heavier armor?