We can only tell you if this is the right forum if you tell us what you want to know about the Avatar with spear/sword.
If it's a question on...
-Whether the spear has different rules then the sword that you wish to know so that you can buy the model according to your preference, then maybe
40k General or
40k Tactics would be a better forum.
-The there is any difference in the lore then
40k Background is the forum you need.
-If you're asking from a modelling point of view then you are certainly in the right forum.
What is it exactly you'd like to know?