Specialty grains are already converted due to the roasting procedure, resulting in a variety of non-fermentable sugars, starches, and very low active enzyme content. All of these factors considered, you will never gain much in terms of fermentable sugars form mashing specialty grains. Partial mash methods depend on the presence of base grains to provide the bulk of the enzymes necessary for conversion.
In short, no mashing specialty grains will not add signifcantly to the fermentable sugar quantity of your wort. However, the presence of base grains in your steeping procedure, assuming you steep in the 148-154F range, (2-row, 6-row, Munich) will.