When the new halloween skin, "Occult-Demoness" is applied to either the OCA-EW 626 'Whisper' series or the Pathfinder (not LR or SD) series of guns, the model will not appear.   In Inventory:   Of all the different weapons I was able to check, it seems to only appear on these: OCA-EW 626 'Whisper' PR1 OCA-EW 626 'Whisper' PR2 OCA-EW 626 'Whisper' RT1 Pathfinder PR1 Pathfinder PR2   In-game images: