Even though the clutch side cover has the Atom logo on it, it doesn't carry a Model Number

A yellow clutch side cover but the starter housing carry's the model number of 704 in grey ?

The saw to your left is a  706 AV

I personally believe that since all the Atoms shared most of there components, it is the clutch housing that represents supplies to various dealers or major resellers by being colour coded.

Another point worth considering as the spare parts dwindled other saws would have been canablised but in these instances the  branded saws would have had the rectangular logo box on the clutch cover carrying the dealers name and model details.

The "Resellers" Chainsaw's

The McEwan Special 18 It would have had the rectangular logo box on the clutch side cover

The story behind the rectangular logo box on the starter housings of the different Atom chainsaw models. I rang Atom Industries in Sydney and spoke with John Notas one of the two brothers involved in the origional manufacturing of the Atom chainsaw and John told me it really wasn't anything really as it was used on the McEwan saws ( i imagine that Atom produced this cover as a later part where it was incorporated into production to use up the housing's made )

Atom Super-Cut possibly a 704