Inside access to gas tank on 76 Suburban

[brentwood]

Hello. I have to get to the sending unit on my 76 Suburban. No gas to the pump even with 1/2 tank of gas. I was told by another poster that his 75 Suburban had a inside access panel to the top of the gas tank. While his 77 Suburban did not. Without tearing up my rear mat does anyone know if the 76 Suburban had this access panel? He said it made changing the unit a 15 minute job. Also is this the whole rear panel or just a small panel right above the tank? Greg