just a quick question are you aloud to give a unit different weapons than they have on the models? becouse I have some saurus with handweapons on the model but I want to use them with spears is that against the rules?
See the Saurus Warrior FAQ for an answer to this question. http://www.lustria-online.com/threads/saurus-warrior-faq-and-strategy.1819/
What you see is what you get is definitely not as enforced in WHFB as in 40k. Having said that, weapons and shields are probably the more important things. If you have a mixed unit with some spears at the front and keep the hand weapons at the back, no problem. In a friendly game where you are planning to expand, it should be ok with your opponents since it is a very minor proxy. At tournies, you won't get away with using a full hand weapon unit as spears.
I keep all my models WYSIWYG just to stave off the confusion that would undoubtedly arise if I didn't. And it is a good practice to keep up if you want to play 40K as well, because as strewart said, it is strongly enforced.
I'll be mixing weapons in my saurus. But at a 1/5 ratio at worst. (so the 10 strong hammer gets two spears. one might even be a champion.) and the 18 strong spear unit gets 3. (actually, might have the front row hand weapons, back two rows spears) but I'm a lunatic who loves rag tag mobs.