There are so many different type wall brackets used that I think it would be impossible to tell you what will work. When I did home theater professionaly and had to service a big wall mounted TV, I would use a mirror and flash light to determine how the bracket worked prior to attempting to remove the TV. The safety latch could be on the bottom or top, seen them both. None more often than the other. If you use a smart phone, might try taking some pictures behind the TV and see what you can get (that kind of "tool" wasn't around too much back then).
2013 Cardinal 3800FL
2009 GMC 3500HD CC LB SRW