I went back and checked the v3, v4, v5, and v6 schematics. All are the same with only 2 GNDREF points on T2 and T4. In the case of T4, it would need to be at the same level as the rest of the board ground in order for the radio to work (Both of the IF amps need it for either input or output). For T2, the antenna connection is drawn connected to the common ground, not GRNREF. Based on this, I do not see any distinction between them. It may have been a holdover from a pre-v3 design, or a simple typo with the copy-paste function when Ashhar Farhan created the schematics. I have not taken my units apart to look, however, I am confident that the shield connection of the antenna goes to the common ground for the board.
May I ask the reason for your question? It is better to know how the answer would be used to ensure that we can give you the information that you want.