The inmate locator should have up-to-date information but never count on it 100%. What time of the day are you trying to call? I used to have a better chance of getting an answer to my call if I called in the middle of the night when central control has to answer the phone. They're able to tell you if your inmate is there, but they don't have the information and if they're able to receive visits or not. Because I would have to leave so early in the morning to get there, I will call before I left at about 4 AM.
You can search through the inmate locator site. https://www.bop.gov/mobile/find_inmate/
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