Not an old SIM card. Ours are Chinese local sets. They give away free Chinese data together each set. The SIM card can actually be used in China if you are heading there.
If it is a sim card inside , it is fine . But the sim card has many line on the contact points which mean it has been use a numerous of time .
My biggest concern is that the IMEI on the tablet (shown the OS ) matches on the box label , the tablet sticker .
But the s/n of the device shown on the OS don't match the box/tablet sticker label .
It sound scarcely right .
I have compare to my mi box serial number both the mi-box and the carton box match accordingly.