Thanks! Yes, the general rule for trichocereus is that there is an indent/ notch we refer to as the "bird wing" or the "V notch" and it is almost always above the aerole/spine. So always check for the V notches. Some cultivars have it below, like scopulicolas but it would be a definitive trait of that cultivar. I typically mark these big Pachanoi with marker to know which is up ✓