YES, As long as the 99 is not the new body design.
YES.
The answer to your question is no. 1988 to 1998 interchange.1999 to 2002 interchange.
Will a 2000 chevy 2500 bumper fit a 2005 chevy 2500
NO
Yes.
Yes.
no
Yes it will fit right on it.
Not if it is a classic 1999 siverado.
yes it will fit
Um... I would sure hope so since they are both 2003. But if you mean "will a bumper from a 03 silverado 1500 fit a 03 silverado 2500, (or the other way around)" I am not sure. It might, but the frame on the 2500 is bigger than that on a 1500.
NO.