Unless I am mistaken, grimoire cards that confer grimoire score appear to have a white/yellow progress meter at the bottom of the card's thumbnail image. I do not believe that grimoire cards not bearing such a meter confer grimoire score. Moreover, the only cards bearing grimoire score in the primary weapons section are: Auto Rifles, Scout Rifles, Pulse Rifles, & Hand Cannons, with kill ranks conferring additional grimoire score. The exotic weapons falling within such categories can be used to produce kills towards those kill ranks, but do not confer score upon initial acquisition of the exotic weapons themselves.