I have attended several ward sacrament meetings over that last few years and I have heard rumors about church safety and the act of conceal carrying in sacrament meetings. I too have noticed a new habit of older gentlemen (some known to be the hunters of the ward) sitting at the top row of seats behind the bishopric, keeping a watchful eye on things. I don’t ever remember growing up seeing these men sitting in this particular area. Could they be there if something goes awry?
The Church’s current policy on concealed carry is that it is forbidden. The Church leaders have recommended and provided policy that the only people allowed to bring a gun into church are law enforcement officers. The Church’s guidelines, policies, with concealed carry are found within the Church’s Handbook of Instruction Book 2, and are located in chapter 21 section 2.4 if you would like to read this further you can go to this link: Firearms.
As to your unique ward sacrament, I honestly would not be able to provide any accurate statement as I do not attend your ward. I have never experienced what you are specifying. I have never experienced anyone behind the bishopric except for speakers, ward choir, or visiting authorities (visiting authorities are usually to the side, not behind).
I would ask your bishop directly if this concerns you, or if you would simply like to know. That is the best way to find out the answer in your particular ward.