That's a repaint on the tank, my '82 LS kinda looked the same when I first got it .
If you have the fine mesh screen over the fuel tap intake tubes, I wouldn't worry about it .
If you don't have that screen, the loose paint falling into the tank may cause a problem with clogging / restricting fuel flow .
Usually, if you have a Karcoma fuel tap, the fuel outlet on the tap is at the 3 o'clock position and has barbed fitting where the fuel line goes on .
If you have a Germa fuel tap, it has a threaded fitting at the 6 o'clock position and has a small plastic mesh filter inside the barbed fitting .
The Germa fuel tap usually does not have the screen over the intake tubes .
But seeing as it's obvious someone has worked on this before, there is no way of telling what you have until you take it apart .