The universal seam allowance in patch or pieced quilting is 1/4 inch, so most all patterns have allowed for that and added 1/2 inch to cutting instructions. this helps you take the guesswork out of calculating. the patterns you see most that do not have a seam allowance added will be applique patterns such as hearts for example. The shape of the heart in the pattern is meant to be drawn onto fabric exactly and then you cut it out approximately 1/8 inch away from your drawn line, unless you do wonder under or steam a seam to fix the piece to a back ground. You would not add a seam allowance in that situation.