OEM batteries are usually reserved to be sold by the manufacturers themself or by factory authorized repair centers, Anybody else that says they are selling OEM batteries is not quite truthful. iFixit gets its batteries from reliable sources and they are manufactured to OEM specs. You may have gotten a battery that was made in the same factory as the OEM battery yet can not have the same label since it is not for the OEM market. Anyhow, if you are that concerned about it I suggest you contact the customer service department https://help.ifixit.com/article/136-email-support and see if they can get this straightened out for you. About your security concern, if it is that important to you I would suggest you get your battery changed by an authorized service center and thus get a factory battery. I am certain that they will love to spy on you as much as the next company.