I still have iPad 1 unlimited data SIM. I'm thinking if we swap that sim for an LTE SIM and give them IMEI of an LTE iPad 3, will the account get provisioned automatically to Unlimited LTE? the apn is the same on hspa and lte "broadband"
As someone that is in the process of upgrading from only a 3G to a faux 4G hspa+ phone they are different plans they told me I had to get my company to switch plans from 2GB 3G plan to a 4G plan, so I don't know if they'll let you transfer unlimited to LTE. It's worth a shot, but it's more than just giving them the imei, the apn's are different for 4G from what I've read.