No, I still haven't found a workaround.. The radio has never been moved to my radio central and the guy I purchased it from vanished. I did find that the radio originated from an internet based Motorola provider that went out of business so the radio never regionalized and in motorola's records doesn't exist. So I'm stuck with a brick that will never read to my RM so I can be able to check the box to do local programming.
So if anyone can hack the thing, I'm open for suggestions ..
Just wanted to provide you with an update. I was able to successfully get my Motorola ION added to my agency and now I can use Radio Central to program the radio.
My suggestion to you, if you haven't done so already, is to reach out to Motorola and tell them that you purchased the radio from someone directly and have no way of contacting that person. They will open a ticket and do an investigation to make sure that the ION has not been flagged for being stolen. Once that clears they will add the radio to your agency (assuming you already have an agency).
If you don't have an agency, you need to email the onboarding team and request for an agency to be created on your account so you can use Radio Central.
Hope this helps, good luck.
edit: Also to add.
There is in fact an option that has to be enabled in the CPS of the ION in order for you to be able to program the radio locally using RM instead of needing Radio Central.
General> Network> General> Programming Connection: On-Premises and Cloud
However, if the seller decides to do a factory reset on the radio and wipes the codeplug before selling it then they are disabling that feature from the radio and this is why you are unable to read the radio using RM.
For anyone reading this and thinking about buying a Motorola ION from someone who claims that you can use RM to program the radio, make sure they DO NOT WIPE the codeplug in the radio before selling it otherwise they are disabling this option.