Experiments with the Foxy P2P network have demonstrated that the first uploader of a file can be identified when search queries are submitted to all the network nodes during initial file sharing. However, in real Foxy networks, file search queries are not transmitted to the entire Foxy network and this process may not identify the first uploader. This paper presents a set of validation rules that validate the observed first uploader. The validation rules define the seeder curve that consistently describes the number of uploaders over time. Analysis of four scenarios shows improved accuracy at detecting the first uploader and that, in situations with insufficient competition for file content, the first uploader may not be identified precisely.