coils and coil-packs

Can anyone tell me if theres a differance between a 95 and 98, 3.8 series 2 coil or coil pack,I can't seem to find any part#s

Same thing, listed below are the part numbers.

1998 : BUICK : LESABRE LIMITED : 3.8L 231 cubic inch V6 MFI (K) : Ignition : Ignition Coil

ACDELCO Part # D555
COIL,IGN {#10472401}

STANDARD MOTOR PRODUCTS Part # DR39X
MFI {D.I.S. COIL}



1995 : BUICK : LESABRE LIMITED : 3.8L 231 cubic inch V6 MFI (L) : Ignition : Ignition Coil

ACDELCO Part # D555
COIL,IGN {#10472401}

STANDARD MOTOR PRODUCTS Part # DR39X
SFI {D.I.S. COIL}

Thanks Z,now the 2 big questions: what size socket or wrench to remove it and how do I test it?Thanks.