Right, this comp request took a strange turn. Anyway, as you Josie have no proof of all this stuff 'not' happening or any proof of anything at all in even owning these guns i am going to have to deny this request.
Whilst i understand it takes a lot of grinding to buy these weapons and may be fustraiting if you do lose them to a bug in this case i believe they were stolen from the vehicle.
Just remember that all the grinding you do does not have to be spent by buying guns. House storage will always be a safer option.