A model of a double auction market of zerointelligence traders was replicated as an agent-based model using the same market supply and demand curves. The original results were reproduced, and these results and other behavior of the model were examined under different schemes of agent activation, both exogenous and endogenous. While the qualitative differences were typically minor, there were statistically significant differences in all the measures of all the markets in the original research and important divergence in the extended evolution of the simulation. These differences have important implications for all follow-on replications of a zero-intelligence trading model, and for the replication process in general