I actually figured this out
for someone else looking to add this in
in the ForumHome --> forumhome_forumbit_level1_nopost
I added this to the top
Code:
<vb:if condition="$forum[forumid]==XXX">
<div><center>
AD CODE HERE
</center></div>
</vb:if>
I also have this wrapped around it if you want to block this from certain usergroups (like donators, etc.)
Code:
<vb:if condition="!is_member_of($bbuserinfo,88)"> </vb:if>