The results of a fit only contain the outputs of the fit itself (for example, parameter estimates). If you want to reproduce those results, you would need to save a copy of the program and make sure you don't change the program's configuration or anything else the program depends on (like your model). The easiest way to do that is probably to make a backup copy of your SimBiology project (sbproj file), so that you can rerun the same program.
That said, you might need to take extra steps to ensure the project contains everything you need to reproduce the results. For example, if you are using a global optimization method that has a stochastic/random element to it (like scattersearch), you would need to ensure that the random number generator is in the same state every time you run the program. The easiest way to ensure that is to configure your program to set the random number generator's seed.
Even then, don't assume that you will get exactly the same results if you use a different computer or a different version of MATLAB. Remember that you are calculating approximate solutions subject to the limitations of floating point arithmetic. Hardware and software differences can lead to changes in the approximations. For simple arithmetic operations, such changes are typicall quite small. When simulating a complex SimBiology model, the differences can compound. And then when you add optimization on top of that, you might see even more differences. You can often reduce those differences by using tight solver tolerances for your SimBiology simulations, and tight convergence criteria for your optimizations.
