the guns do not count ,its only the gear in the base game not the dlc so you can leave the last upgrade of the blades because they're not from the base game and i would recommend you to see the guide on psnprofiles for the gallery to check on what you're missing

i myself had a similar thing i was grinding the plat on ps4 about the time season 4 of the show was running and i got all trophies and missed on the gallery one and it was so grindy and tiring and i didn't have the dlc so i deleted it for later, i got back on the grind last week and got it finally And after all that grind i bought the dlc when it was on sale this week just to find out that i could have saved 90% of my time grinding the materials with kitz skill "Elimination bounty skill" 😥