Default Buying a used ATT S4, can I have ATT look up phone to make sure I can activate?

I have been on Sprint for over ten years and I am used to buying used Sprint phones, all I have to do is call Sprint and give them the ESN and they tell me yes or no for activation.

I know GSM phones are different but I thought I read that a GSMs phone IMEI (spelling) can be blacklisted or blocked, is this true? If so will ATT look up the number for you to confirm it is ok?

Looks like I am moving my family plan from Sprint to ATTs 10GB family share plan, I will keep using my Nexus 5 but my wife has an S4 for Sprint so I need to buy a used S4 for ATT.

Thanks
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Nexus 5 - 32GB Black - Unlocked & Rooted
TWRP
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RIP - OG EVO - Wife killed the power button
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