I keep seeing and reading conflicting information about what distinguishes the difference in the models. Based on some homework, the variance is in the notching of the cylinder, and squared backside of the trigger guard. But, here's the confusion: different places tell me the 1st model does indeed have the squareback guard, others say no. And still more confusing, different resources say different things regarding the cylinder notching for each model.
Where is the definitive answer?
Where is the definitive answer?