I believe so. The idea of MVC is precisely separate responsibilities of the various components and even the tasks to be performed in the project.
But if you consider layout is never ready doesn’t make so much difference. Each can find their best project management model. This may vary with the specific quantity and qualification of your members.
Some may say that the whole backend (model and controller) should be done before and with the proper specification of this the responsible for mounting the HTML should build the layout as you wish. Others will prefer to build HTML and from there begin to specify what the controller should do and define how the model. The two approaches can produce better and more productive results under different circumstances.
Try both and see which is best for your case, when you have experience, you will know to choose beforehand in each case. Obviously a hybrid solution is possible.
What is certain is that you need the requirements first, even if obtained informally. It just can’t be in the achometer, Amazingly enough, a lot of software is done without it. It can be dangerous to do the layout to find the specification, but there are cases that, done carefully, may be a valid option.