Yes, the malt will drop the mash ph, but you need to know more about the water you're using than just its starting ph. You need to know the alkalinity and the concentrations of various ions to be able to determine where the ph will end up once you mash in (see the Water Input tab). Spotted Cow is a pretty light beer, so unless you have naturally soft water you'll probably need to dilute with some distilled water to get the ph low enough. You're shooting for 5.2-5.6 or so as a mash ph. A recipe and water report would be needed to be more helpful in telling you what you need to do though.
If you want to just build you water profile using all distilled water, which isn't a bad idea for this beer, just change the dilution percentage on the Water Adjustment tab to 100%, put your grain bill into the Mash Acidification tab, then adjust the water additions (gypsum, calcium chloride, lactic acid in this case) until you get the ph on the MA tab to be where you want. You'll probably need somewhere in the range of 1gm/gallon of gypsum or calcium chloride to get there.