I have a stew recipe calling for dark porter beer. Need a brand name. Have Guiness. Will that work?

I ama former chef and have used porter myself in dishes, it is a bit sweeter and less malty than Guinness add abit of dark brown sugar with it about 2 tablespoons when adding the beer/stout, and cook it the same way as the recipe asks for the porter, Porter was made for the workers on the docks in the UK and it was a bit different than lager, bitter, ale and stout.