There is a couple things to take into consideration with this. One being the dosage of caffeine. I am not sure what the conversion would be for that amount into a rat compared with a similar dosage in humans. Typically, in research, the dosage is plenty high to illicit a particular effect. If it does translate to a relatively high dosage of caffeine for humans, then it stands to probably show the same pattern of reduced GLUT4 expression via decreased insulin sensitivity.
With a high enough caffeine dosage, there tends to be a significant cortisol response which could decrease insulin sensitivity and thus GLUT4 expression. This may not be the case with a more "normal" dosage of caffeine though, or at least it would contribute to a response that wasn't very significant.
Another thing to take into consideration when referring to caffeine and working out is that there are two mechanisms by which GLUT4 can be expressed. One is insulin mediated, and the other is non-insulin mediated. Insulin mediated GLUT4 expression, as you probably guessed is elicited by insulin. Non-insulin mediated GLUT4 expression is elicited mechanically, via exercise.
Point being, if you are consuming carbs and then exercising you harnessing both insulin and non-insulin mediated glucose uptake, potentially diminishing what drawbacks caffeine may have on GLUT4 expression.