I'd have to agree with Cowboy, check Tech Readouts, if original design had hands, then make them look like hands.
This for the most part.
With all due respect for their work, I didn't care much for the 'face' on the MekTek-added MW4 Fire Moth/Dasher, either. OTOH, the 'not-really-a-face' on the MW4 Executioner/Gladiator ended up looking goofy, IMO(and the painfully stretched/low-res textures on the torso didn't help).
On yet another hand: Technically, the Gargoyle/Man O' War should be considered to have hands 'by default', but its Primary configuration uses arm-mounted light autocannons, and the construction rules don't allow hands on OmniMech arms that have ACs, Gauss or PPCs equipped(which is why the Executioner is also only shown with one hand). All but two of the canon alternate configs have a hand on one arm or the other(or both, in the case of the D).
...
Actually on further review, about as many of the 3050 Clan Omnis have hands as don't; for the most part, it's really only the iconic heavies(Mad Dog, Hellbringer, Summoner, Timber Wolf), and the Dire Wolf and Warhawk that exclude them almost entirely.
Still, for the most part, 'check the TRO art' is probably good precedent if there's any question.