Yeah, if you're taking them for offense, take great weapons, but if you want a tougher unit, and it's at all an option for you, take tomb guard with their superior tomb shields. If you do field tomb guard, you're far better off with swords than halberds. 3+ to hit, 4+ to wound from the swords on the surface looks the same as 4+ fto hit, 3+ to wound from the halberds, except that like grave guard they get double damage on 6s to wound, and more successful hits means more wound rolls means more 6s.
It's not a huge difference, you can go with halberds if you like the look of them a lot more, but they're technically just not as good.
Both are better than grave guard with shields, though, because the tomb guard shields are just that much better.