While fighting Shiki and his massive fleet, it was shown that Roger wielded a sword in one hand and a gun in the other. Roger also wielded a sword in the fight against the Rocks Pirates.

Then he used a sword against Whitebeard in their final fight.

Is Gol D. Roger’s sword one of the 12 Supreme Grade Swords?

Just compare the 2 images below, I think it’s self explanatory.
From chapter 912:

From chapter 966:

*by whynot49lv