What is the name of the exchange?
I honestly do not know how IEO works. I doubt I have ever seen IEO projects before aside from those on forum members signature. but I will suggest you invest in those on reputable exchanges. However, if you want to take risk on new exchanges that is up to you. Just don't invest what you can't afford to lose.
Why do you want to invest in the coin by the way? Have you researched into the project to know whether it is scam or not?
Do not worry yourself about it. Do not go looking for answers. They tried IEOs after ICOs stopped working,,, and now believe me, IEOs are also beginning to fail, but we always knew that. If you want a coin so badly, let it perform first, and then just go to an exchange to buy it if you decide to support it (or mine it).
IEOs are the new ICOs. And therefore they are the new scam methods.