So...
The history we have learned on these short two-man saws is that they were used for free hand slabbing. Apparently in the early days a second man on the other end of the saw was an aid to help in keeping the cut straight for a better board without a guide. So in answer to your question, this restoration was done to be historically correct, not necessarily to satisfy someones, uh... bar envy.
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Bar envy had little to do with my comments, I just thought that any saw as heavy as those Mall saws are should be able to cut a bigger log. If me and another man had to tote around a 70lb. saw for a little 20" log, I'm not entirely sure that I wouldn't prefer to just get a "misery whip" and have at it.
Of course I am far from being a historian of the old chainsaws, but I don't think very many folks ever tried ripping planks with my version of a Mall 12a. It has 3/4" pitch chain on it, and I am certain that it turns pretty slow with that old engine and the gear drive. It certainly does not have ripping chain on it.
I always believed that the rotating bar alignment was so that the float carburetor would always be "up". This slow turning old behemoth would be a nightmare to control for kickback (BIG bite on the chain, and slow turning!), and I always thought that the 2nd man handle was as much for eliminating the tip of the bar as a cutting zone as it was for helping to carry the saw during a cut.
I suspect that the popularity of the bow saws declined when kickback became less of a problem with the faster lighter saws. The very slow, gear reduction saws relied on huge torque and big chain to make a cut. Of course this eliminated any practical use of the top of the saw, so a bow saw was a safe improvement on a two sided bar that could only be used on the bottom edge.
My father told me a story from his youth about this very topic: it seems that he was on a work crew of some sort using a chainsaw, and the foreman rudely took the saw from him for not using the right technique...and then immediately proceeded to get a tremendous kickback from the saw, which threw him backwards onto his buttocks, impaling him right up the rectum on a sharp stump. OWW!! Not being a terribly sympathetic person, my father seemed pleased that he was no longer obliged to listen to the foreman after that fellow was hospitalized. My guess would be that my dad continued to use the saw in the same manner as he had prior to his "lesson" by the foreman. He wasn't well known for his gentle manner, nor his ability to follow rules.