Yes, laced spokes need to be added in a certain order (heads-out first, heads-in last) so that you can properly manipulate each spoke coming in. Once they are all in place, it is hard to do a head-out spoke. Sure you can replace one or two in a pinch, but you wouldn't want to do a whole rebuild that way. You can remove all the heads-out spokes then do the heads-in spokes one at a time. Then put the heads-out spokes back in. That will help simplify things by preserving the lacing pattern without getting the spokes all tangled up.