No, not a Scam. A lot depends on the project team, which should be ready to implement all the plans, and not just to raise money.
Indeed even bitcoin doesn't have whitepaper even it launched. Even the ico have whitepaper it doesn't mean that they won't be a nuts and in fact they use their whitepaper to look a legit one.
Likewise, we need to check every aspect that we can think of and not just by looking in whitepaper or else our hard earned money will just go to their wallets