Without much proof it is hard to tell if a coin is being manipulated much in an exchange. However, like someone suggested, it is wise to take your time and observe the charts and trading volume of the coin for a couple of days before jumping on the train to buy
This will be something hard to do, most especially if the project team is the one selling. Such token will continue to dump until there is nothing meaning, left to sell to.
A lot of projects have done this and they are still doing it. They can definitely manipulate prices, to attract investors and make them buy. It is very risky because they are disposing of off their tokens while taking investors' main coin. i.e, their token for your BTC.