I know there are websites that answer most repro and color questions but I'm writing this list out anyways, as I've spent 6 months bending, comparing, dropping, and analyzing what feels like 1000 weapons and I'd hate to see all that time wasted. You should have seen the look on my wife's face the first time she saw me dropping weapons on a table.

It's been a very frustrating and expensive learning experience to say the least. How many figures did I buy complete only to have to sell them back weaponless for a quarter of what I paid. If I get a repro it goes right in the garbage. Anyways hopefully it helps someone one day.
This list doesn't deal with repros as much as it deals with colors. Keep in mind that in some cases figures were packed with the wrong colored weapons, particullary with Tri-Logos. They are not listed of course as they are the wrong weapon.
Things to watch out for:
Painted weapons; In almost every case Kenner weapons are supposed to be molded in the color they are. If you think the weapon is painted (It appears too glossy), scratch it or bend it, if the paint comes off it's a repro. The repro lightsabers are often painted.
Color; So many repros are the wrong color. Blue, Grey, and Black are the often used wrong colors. If you have a grey Stormtrooper blaster or a Han blaster it's a fake.
Bendable; Repros are often not very flexible and will sometimes snap or feel like they are going to when bent. They are often resin based and will be very white on the inside. You want to see the same color on the inside that you see on the outside. (Although there will be white stress markings when bent on a real weapon)
Drop Test; The really crappy repros are easy to hear when dropped. They have a high pitched sound. Use this when you have a real one to compare.
Star WarsLuke Skywalker:
YellowChewbacca:
Black,
Green Princess Leia:
BlackStormtrooper:
BlackHan Solo:
BlackDSC (Stormtrooper Blaster):
BlackBen Kenobi:
BlueJawa:
BlackSand People:
BrownDarth Vader:
RedGreedo (Han Blaster):
BlackHammerhead (Stormtrooper Blaster):
BlackSnaggletooth (Han Blaster):
BlackWalrusman (Stormtrooper Blaster):
BlackLuke X-Wing (Han Blaster):
BlackBoba Fett: (Stormtrooper Blaster):
BlackESBBossk:
BlueUgnaught (Bag):
WhiteBespin Security Guards (Bespin Gun):
BlueImperial Stormtrooper Hoth (Dengar Rifle):
BlueLando (Bespin Blaster):
BlueLuke Bespin (Han Blaster) (Saber):
Blue Yellow Han Solo Hoth (Han Blaster):
BlueLeia Bespin (Leia Blaster):
BlueLeia Hoth (Leia Blaster):
BlueRebel Soldier: (Bespin Blaster):
BlueYoda (Snake):
Orange Brown GreenDengar (Dengar/Snowtrooper Rifle):
BlueHan Bespin (Bespin Gun):
BlueLobot (Bespin Gun):
BlueAT-AT Driver (Luke Hoth Rifle):
BlackLuke Hoth (Luke Hoth/AT-AT/Rebel Commander):
BlackImperial Commander (Stormtrooper Blaster):
Blue2-1B: Silver
Rebel Commander (Luke Hoth/AT-AT/Rebel Commander):
BlackAT-AT Commander (Bespin Blaster):
BlueCloud Car Pilot (Nien Nunb, CCP, Tie Fighter Pilot Blaster) (Commlink): Grey
Tie Fighter Pilot (Nien Nunb, CCP, Tie Fighter Pilot Blaster) Grey
2-1B: Silver
4-LOM:
BlackZuckuss:
BlackROTJAdmiral Ackbar:
BlackBib Fortuna:
BrownBiker Scout: Grey
Cheif Chirpa:
BrownERG: Grey
Klaatu (Lando Skiff/Klaatu/Weequay): Grey
Gammorean Guard : Grey and Brown
General Mandine:
WhiteLogray:
BlackLuke Jedi (Lando General/Luke Jedi/Luke Poncho): Grey or Brownish Grey
Ree Yees: Gold
Rancor Keeper: Grey
Squid Head (Bespin Blaster): Grey
Weequay (Lando Skiff/Klaatu/Weequay): Grey
Klaatu Skiff: Grey
Rebel Commando:
BrownLeia Boussh:
BlackNikto (Yak Face/Nikto/Barada): Grey
Emperor:
BlackAT-ST Driver (Leia Poncho/AT-ST Driver/B-Wing/Imperial Gunner/Awing):
BlueB-Wing Pilot (Leia Poncho/AT-ST Driver/B-Wing/Imperial Gunner/Awing):
BlueLeia Poncho (Leia Poncho/AT-ST Driver/B-Wing/Imperial Gunner/Awing):
BlueHan Trench (Han Blaster):
BlackPrune Face:
BrownTeebo:
BeigeWicket: (Wicket/Romba)
Brown Lumat (Lumat/Warok Bow):
Light Brown/OrangePaploo:
BrownPOTFImp. Gunner (Leia Poncho/AT-ST Driver/B-Wing/Imperial Gunner/Awing):
BlackA-Wing Pilot (Leia Poncho/AT-ST Driver/B-Wing/Imperial Gunner/Awing):
BlackLuke Stormtrooper (Stormtrooper Blaster):
BlackYak Face (Yak Face/Nikto/Barada): Grey
Barada (Yak Face/Nikto/Barada): Grey
Luke Poncho (Lando General/Luke Jedi/Luke Poncho):
BlackLando General (Lando General/Luke Jedi/Luke Poncho):
BlackRomba (Wicket/Romba):
BrownWarok (Lumat/Warok Bow):
Dark Brown