It doesn't matter which one it is. There are no IMEI numbers listed in the VZW servers to get a normal activation done. You have to only have the sim working to get the phone to work.
Yes but you didn't buy the phone at t-mobile....
Doesn't matter. It's all the same phone.
Actually, Closingracer is likely correct. Sprint and Verizon (the CDMA carriers) maintain the list of the IMEIs that they will permit on their network (regardless of whether the device has compatible hardware). If your phone's IMEI is not on their approved list (maintained on Sprint / Verizon's databases), you cannot get it activated with Sprint/Verizon.
The devices purchased from Moto and from Google Play have their IMEIs added on Verizon and Sprint's databases, so you can get them activated on their networks (I believe Moto N6 devices initially had problems getting activated on Sprint, but they got those IMEIs added and then activation was successful). Devices purchased from T-Mo/AT&T did not have their IMEIs in Verizon/Sprint's databases initially, so getting them activated on Verizon/Sprint was not possible.
Reading this, it looks like Verizon did permit that device to be activated - likely because they either added the IMEIs, or because user used the SIM from the previous device.