Happy to help!
A quick way to "prove it" is have the Best Buy folks throw in an AT&T (or Tmobile or Cricket) SIM, reboot, and I bet you it will MMS with no issues.
Almost forgot: you may need AT&T to add your Note 8's IMEI to their network. But, for a short test, it might not be required. Example; I have put a Sprint SIM card into my device and it worked fine even though I am with a different carrier. I was just testing an my unlock Xfinity provided me.
If the AT&T SIM is active (part of a paid plan you are up to date with) and provisioned for MMS; it will connect to AT&T network and have full capabilites of AT&T network (as far as what featuers you are paying for on AT&T network and the SIM is not "locked" to another IMEI).
It will not clear up your Verizon issue.
It is simply a way to prove the GSM factor that is limiting your devices features.
The beauty of unlocked devices is supposed to be you can use it on any network whenever you want (so long as you are paying for the cell service and nothing "funny" is going on).
However, I believe your case to be that you will find the device functions fine on any GSM network, but will have issues without "other modifications" on CDMA networks.
Since I am outside of the 14 day window, Best Buy suggests that I use the manufacturer warranty for a replacement device. The difference in the model numbers appears to be a color change from midnight black to orchid gray.
So, despite the fact that the 1 is dropped from the Unlocked Galaxy Note 8 model number on the website, the several devices I ordered and inspected all have the 1 following the model number. I walked out with a Verizon Galaxy Note 8 and after switching on the Advanced Calling option the device is able to talk, surf, send and receive MMS during a call. Verizon says this option is
missing from the unlocked version and this prohibits unlocked devices from fully accessing