Heya!
I don't use the CSM settings in ya Mod n just stick with some defaults, however I do use AddSignalPistolToSpec
I noticed that on a previous profile(Standard) that my Flare Gun could be added to Special but now the change does not work on an Unheard profile.
Went and once overed the SVM.js and I see that you _tpl the pockets item "627a4e6b255f7527fb05a0f6" called "Карманы 1 на 4 со спец слотами", that's the Standard pockets! Yep!
But for the Unheard edition, I'm pretty positive that it's item "Карманы 1 на 4 TUE" aka ID: "65e080be269cbd5c5005e529"
So because of that any changes to the Pockets (such as AddSignalPistolToSpec) will not work.
I personally just edited SVM.js and changed the ID of original pockets everywhere it was referenced to the ID for Unheard's pockets and it fixed that issue.
Hope this helps ya!