Support for the MTS2000/MCS2000 ended a few years back (2010 IIRC). I am not sure if Flashport upgrades are being sold by Motorola, but there are some folks in the radio community who may be able to help you.
Problem is shipping your radio to and from may exceed the value itself and as you've said, buy one that already has the desired feature set flashed in.
One caveat about Ebay MTS2000s, most sellers don't know a Flashcode from a hole in the ground and the rear chassis tags may not always match what is inside.
If they are willing, have them put the radio in field test mode (press lower side button 5 times within 10 seconds of power on) and read the flashcode and firmware version to you.