This will produce the correct decimal value you want:
int decValue = int.Parse("8496FC", System.Globalization.NumberStyles.HexNumber);
As you can see the hex value used to produce the decimal value consists of the following colour components:
B (84) G (96) R (FC)
with the A component dropped.
This can be calculated by using a substring
on your full hex colour like so:
string colour = labelcolor.Color.TrimStart('#');
string R = colour.Substring(2, 2);
string G = colour.Substring(4, 2);
string B = colour.Substring(6, 2);
Which you can then use like so:
int decValue = int.Parse(B + G + R, System.Globalization.NumberStyles.HexNumber);
//decValue = 8689404