Hmmm? AJ says yes, but I say no...and not just no, but heck no! In addition, the adjustments he goes on to recommend will make it much worse. He keeps quoting a Michael Lewis recipe for a stout that bears little resemblance to what many brewers use in creating their stouts and porters. If there is any crystal in the OP's recipe, the mash pH will be lower than desirable and the beer will be thin and tart. Since most drinkers enjoy their stouts and porters thick and round, I recommend a starkly different approach.
The alkalinity of the OP's water is quite modest and is a great place to start for many beers. But in the case of a more acidic grist like a stout, it probably doesn't have enough alkalinity to help maintain a proper mash pH.
There are a couple of options for avoiding a low pH in this case. The easiest is to not add any hardness minerals (Ca, Mg) to the mashing water. Add those Ca and Mg additions directly to the kettle. This avoids further depressing the RA of the mashing water, which depresses the mash pH. Another option is to reserve the crystal and roast malts from the main mash and add them at the end of the mash. Another option would be to add alkalinity to the mashing water to neutralize the acidity contributions of the roast and crystal malts.
Any of those options could be feasible. I'm surprised that AJ didn't mention that you should check the mash pH to assess if his recommendations were suited to your brewing, but maybe the Primer mentions that. A pH meter is the best option, but I suggest that Bru'n Water can provide a decent estimate of how the mash pH will respond. It also gives a brewer the chance to check out those options I mention above.
I certainly invite you to use AJ's recommendations, but I implore you to report back here with your results. I'm pretty sure you'll parrot my remarks.
Enjoy!