No, not a scam. Those who offered their support and interest on the announcement thread were freely given PMC. I was there and recieved a few thousand. Anyone who posted an address got some. The coins were near worthless at the time so they were rapidly spread with users encouraged to reach as many people as possible. Sorry you missed out, but even now if you do something useful, or even post your address, you'll get coins from the community.
Here is a description from the dev, posted on forums.premine.co.in, about the distribution.
Since the last of the DEV wallet is almost passed out, we think it will best to make a post about this. It is already a common question and for the purpose of documentation we will address it here.
After Premine was launched, we began passing out coins immediately. The handouts were given in the largest amounts to the pre-launch supporters, and early adopters. All coins were passed out with the hope that they would be passed out to others by the recipients. The Amounts ranged from 5000-10,000 per address, favoring the lower end.
Word spread, and more and more addresses started coming in. The giveaways were tapered off gradually. This continued for approximately 7 days. During this time the announcement was translated to ?German, Spanish, and Chinese. Bounties were given to the good and generous people who took the time to spread the word, as well as funding for people who offered to do various giveaways.
Additionally we opened a twitter account to give away coins, volunteers set up reddit, facebook, and IRC contacts. As well as a personal forum, and the first block explorer. Gratuities were obviously given, and we continued to pass out coins in a gradually reducing manor. Finally a dice game was set up with a 10,000 bounty and a seed donation. Two faucets were also opened. There was a controversial bounty of 50,000 coins set on the faucet, and because two faucets arrived within moments of each-other the makers agreed to a split. The individuals who made the faucets also very generously donated their bounties to their faucets. Everybody was encouraged heavily to pass as many coins as they could on to somebody else.
We continued to pass out coins to anybody that requested them. And funded various promotions and giveaways. We eventually arrived at two exchanges. A giveaway of 1500 PMC was donated to Poloneix exchange to host a giveaway. The recollection of the events above may vary slightly in the order in which they are documented, but everything should be easy enough to verify if you need to research the announcement thread on BCT. Some users also made scripts to give away coins as fees for the miners, appropriate donations were provided to enhance mining with TX fees.
As of the time of this post we are promoting Premine with a weekend giveaway, the remainder of the coins will be passed out, given away, and donated. We will edit this thread when necessary.
Also, if we forgot to credit somebody above by all means contact one of us. A HUGE number of people pitched in to make this happen, because our community is active. It was a very busy distribution, so I could have easily forgotten somebody
Thanks for your support!