I recently purchased an infantry lot on ebay with some Skinks, warriors, and knights. The warriors and knights are fine, but the skinks seem off. I don't think they are supposed to be wielding a shield attached at the shoulder and/or two separate different weapons. Guess they could be used interchangeably? Don't have the assembly instructions, but have been thinking about detaching the arms and reassembling. From what I understand they can have javelins and shields, boltspitters and shields / clubs, or shields and clubs. some examples in the attached image Thanks!
Your right in that they only wield one weapon + shield but saying that the models shown are fine as long as you use only one combination through each game, just tell your opponent before hand.
This covers all your bases for changing weapons, but as @Crowsfoot said, you have to make it very clear to your opponent which combination you are using.