Transfer function of a real operational amplifer
You are trying to create a detailed model of a sloppy process.  For one thing, the gain-bandwidth product is a minimum spec, or sometimes even just "typical".  The actual gain-bandwidth can be quite different for any one part, and I wouldn't count on the phase margin either.  The raw DC gain can also vary a great deal, as can other parameters.

Getting this detailed is useless for circuit design because the point is to have the circuit work with the minimum guaranteed parameters, but keep working for higher ones.  If you are looking at this level of detail around what a 741 can do, then you are using the wrong opamp.