On Saipans, you can't go by a standard. But you can observe the true Saipan fowl photos very closely and develop an eye for them.. You can also talk to breeders that carry true Saipan, but finding them is like finding a needle in a haystack, I only know of one who may have them and he never would answer me directly to tell me whether he had them or not (which I don't blame him, and for that reason I won't disclose who he is or how to contact him).
The same fellow can be quoted saying, (and I'm probably paraphrasing a little here) that "anyone with real Saipans aren't going to let them go."
The general idea that a high set tail Saipan is a cross stems from the idea that they are Oriental, finding a Oriental that does not carry their tail below horizontal, or horizontally at the highest isn't common for one that is pure. You will sometimes see stags that have a tail set above horizontal, even up to a year old, but by two years their tail normally drops down to be horizontal in all of the cases I have seen. I'm not saying it isn't possible, I am just saying that generally speaking it doesn't happen. All of the old Saipan pics I have seen cocks carried their tail down low, they were large birds typically with a platinum/light red coloration and a walnut comb if I recall correctly.
But: Whatever they may be, they look typical of most other "saipan" fowl I have seen, which has all been hatchery stock as that is about the only thing you will ever find for sale. I say regardless of the above, they're nice looking birds and if you like them get them.
