Select the gun you want equip it scroll to the next copy of it say for instance you have 45 from honest hearts go to a different 45 highlight it with your mouse or Scroll down with the D pad for controller users and press the L key on your keyboard simple as at least this is how it is done as of writing this 12/12/24

 currently available

AAA from Tammers nif bashed weapon pack
CFWR from classic fallout weapons remastered

      EditorID: DLC02Weap10mmPistolSilencedWasteland
      EditorID: DLC02Weap10mmPistolWasteland
      EditorID: NVDLC02Weap45AutoPistol
      EditorID: NVDLC02Weap45AutoPistolUnique
      EditorID: Weap10mmPistol
      EditorID: Weap10mmPistolSilenced
      EditorID: WeapNV9mmPistol
      EditorID: WeapNV9mmPistolUnique
      EditorID: WeapNVSilenced22Pistol
      EditorID: WeapPreord10mmPistol
      EditorID: WeapUniqueColAutumns10mmPistol
      EditorID: aaaWEAPSecretPolicePistol
      EditorID: WeapCzechPistol
      EditorID: aaaWEAPCompact45Pistol
      EditorID: CFWRWeapClassicMDEagle
      EditorID: Weap32BurstPistol
      EditorID: aaaWEAP44MagnumAutoloader
      EditorID: Weap32Pistol
      EditorID: Weap32MachinePistol
      EditorID: aaaWEAPUniversalServicePistol45
      EditorID: aaaWEAPUniversalServicePistol10mm
      EditorID: aaaWEAPUniversalServicePistol9mm
      EditorID: aaaWEAPSemiAutoMagnumPistol
      EditorID: aaaWEAPSecretPolicePistol
      EditorID: aaaWEAPPoliceDutyPistol
      EditorID: aaaWEAPMiniMachinePistol
      EditorID: aaaWEAPMicroMachinePistol
      EditorID: aaaWEAPCompact45Pistol
      EditorID: Weap32MachinePistolUnique
      EditorID: CFWRWeapClassicUniqueDEagle
      EditorID: CFWRWeapClassic6520Pistol
      

 they seem alright which is not surprising considering the top 2 are from a different mode file I've merely expanded on it
      EditorID: WeapShotgunSawedOffNPC
      EditorID: WeapShotgunSawedOffUnique
      EditorID: WeapShotgunSawedOff
      EditorID: WeapUniqueKneecapper
      EditorID: WeapShotgunSawedOffDC


 they do not work right look right wonky
      EditorID: NVDLC04weapflaregun12ga
      EditorID: NVDLC04weapflaregun
      EditorID: flaregunconverted


With new Vegas weapon overhaul the main one for guns it loads on the front magazine not from the grip like vanilla  other than that fine  all the animation for reload is already two different they fire fine but the reloads look wonky
      EditorID: NVDLC05WeapNV127mmPistolUnique
      EditorID: WeapNV127mmPistol
      EditorID: CFWRWeapClassicMC96
      EditorID: DLC02WeapChinesePistolWasteland
      EditorID: WeapChinesePistol
      EditorID: WeapUniqueZhuRongChinesePistol
      EditorID: aaaWEAPUrbanAssaultPistolFullAuto
      EditorID: aaaWEAPUrbanAssaultPistol
      EditorID: WeapChinesePistoleva


if you wish to edit the akimbo text files for either the pistol or double barrel simply add another line make it look like the ones in the file including the word editor ID and the spacing and you can add pretty much anything from any mod items included a most weapons from the base game DLC is included

TTW
classic Fallout weapons remastered the D eagle unique D eagle and Colt 6520 10mm pistol
some of the 32 pistols from TTW 32 Caliber Weapons Pack my expansion TTW 32 Rearmed Combined included a lot a lot of the pistols from Tammers nif bashed weapon pack