Hi Kelly,
I am not a H.S.B. historian so I can’t tell you anything that a quick search on the web won’t bring up. It sounds like a typical “transitional” jack plane and I understand that Sargent and Stanley produced planes for that hardware company. I do own a couple of the Revonac metal planes and really like them.
I treat the soles of my “transition” planes the same way I do fully wooden bodied planes. Normally just a light jointing of the sole is sufficient. If you really want to set the plane up as a true jack then minor depressions or grooves in the sole really won’t matter much in use as long as they don’t allow the plane to rock or dive in use (think about corrugated soles on metal planes and the relieved areas on Japanese plane soles). If you want finer work then you need to take more care with the sole and may have to patch (re-mouth) the sole to close up the mouth to help prevent tear-out. A little boiled linseed oil and some paste wax will finish the raw sole. “Transition” planes (and wooden planes) can really do some wonderful work if tuned and don’t receive their fair amount of attention in the woodworking world. A lot of folks think that there was a manufacturing progression from wooden bodied planes, to “transitionals”, and finally to the metal planes we’re are all familiar with. The manufacturers actually made all three at one time in history and the “transition” planes were highly regarded particularly by carpenters who valued the feel of “wood-on-wood” and enjoyed the lighter weight over the metal planes when it came time to pack up the tools to move on to the next job. They are subject to many of the issues of wooden planes but they are great tools nonetheless.
Have fun