Yes it is a different one. NET stands for Nimiq Exchange Token, an ERC20 Token on top of the Ethereum Network that will be redeemed for NIM in the Nimiq Blockchain once we deliver the Mainnet (December). The one you mention is Netcoin, a Litecoin/Peercoin Hybrid from 2013. We are defining how to make the dissimbaguation and will post it in our Blog