Yea, borken link.
OBD has the very obvious OBD plug locations. If you're lucky they'll know that it's preOBD (wich a ref would know for sure, but is more likely to know what's stock) and skip over looking for the plug to begin with.
A cop would probly never know. I bet I could pass any RB motor NA with a cop (yes i realise that my title revolves around cops), but the bi-annual test i'd either have to really try to make certain aspects of the motor dissapear, or change the motor every other year (wich i'm willing to do, since even if a cop sent me to a ref, i could change the motor). But that means I need to have stored in a garage a motor, tranny, driveshaft, mounts, ect. And lets not even get into the idea of swaping the harness. That's just nasty to think about.