Unlikely, most new cases come with the standoffs in a bag with the "other stuff" but it should be either clearly labelled inside the casing itself via the direct name or a code (Liker A, B or C for mATX), check your user manual when you get the case for the code for mATX and make sure the standoffs are set to that config. Its pretty straight forward once you get the case mate, worst case you can hold the motherboard over the case holes to get an idea of which ones are required.
Just to be clear there is usually a letter imprinted in the metal of the case at each standoff location to indicate which board requires a standoff in that location...
Don't do any of your build on Carpet, generates static !!! Free tip of the day