One school of opinion is that the 'witness' got the reggie wrong. 3X-GOM has never been registered (or seen by anyone else), 3X-G
DM is a different ex-AA 727 (ship 862).
http://727.assintel.com.br/acid/images/3x-gdm_01.jpg
(despite the caption on the above photo, the Benin crash airplane was 3X-GD
O).