There were several types of revetments used in SEA. Even on the same base you could see several different types used. Even the steel revetments were different. Some were like the picture shown and others used roll formed steel and were filled with concrete, sand or dirt. Not all were capped. The revetments at Tan Son Nhut where we kept our RF-4C's had grass growing out of the top. They were rolled steel revetments. The RF-101C revetments were solid concrete walls. In the Charlie area they had the steel formed revetments, as in the A-37 dio. Take your pick and use reference pictures.
Berny
Phormer Phantom Phixer
On the bench
TF-102A Delta Dagger, 32nd FIS, 54-1370, 1/48 scale. Monogram Pro Modeler with C&H conversion.
Revell F-4E Phantom II 33rd TFW, 58th TFS, 69-260, 1/32 scale.
Tamiya F-4D Phantom II, 13th TFS, 66-8711, 1/32 scale. F-4 Phantom Group Build.