I'm not really sure what you're asking. If the vent is closed, as it should be, then you won't see any veins. Either sex can evert tissue when seriously stressed (or "popped") and that will have veins...male or female. And either sex can suffer a prolapse of either sexual or colon tissue which will also show veins and would need immediate attention.
For the sake of understanding please try to be more specific in your questions...
Do you mean that the VEINS are exposed outside the body? If this is the case it may be Prolapse. Google it.
If you mean when the snake is being sexed as in popping and exposing the organs than yes it is normal for a male to appear red in that area. Yes also to a female not looking bright pink and red...
You have anything to add and I am more than happy to help just let me know. I hope I answered as best I could....