My Comm 10 is SN J1018. It is just as described as above: swiftmatic, split rims. I use mine for mowing with a sulky and 30" deck and this season I actually plowed snow. I do have 2 rotary plows but have yet to mount and use. I do not have "lawn" per se but some rough terrain covered in natural grasses for this altitude and rainfall. I cut the grass to minimize the wild fire hazard. I can do most of it while on the sulky and in high/high. I have removed most of the rocks so I can cover most of the area without too much trouble.
I will probably be corrected but it appears that when the modifications were made for the 10A, Gravely went with the internal charging and bendix type starter. Is that correct, guys? It's what the Comm 10 and Comm 10A manuals show. I have both because when my dad acquired this machine 35 years ago, he did not know what he had.
I have another thread about a problem I had recently. It may be useful to you.