Okay so I have probed all the doubled die sites, and the closest I could get to "thick FG" was coppercoins ddr-003,
But I know its not that because the only thing that is showing possible doubling is the FG, Ill show you that in the picture. So here is the coin in question, and follow will be a duller brown 1999 D cent to compare the FG.


And now here is to compare the FG of a different 1999 D Cent

Thank you for looking!! :)