From your description and photos and from my advertising brochure it appears you have an early "Master Gardener (K6CH)". The brochure says powered by a B&S 5 HP, 24" diameter x 9" shredding chamber, 42 fixed teeth, 315 lbs. In 1985 Santa brought me a "Rancher (K8CH)", B&S 8 HP, 24" diameter x 14" shredding chamber, 54 fixed teeth, 470 lbs. The wider stance may make mine a little more stable, but the single pivot front axle still makes it tippy when pulling 90° from the long axis.
I think he said he got it in 1969. It works fantastic, simple but no safety anything.
My machine did have a sheet metal shield over the dual "B" belt drive. The parts diagram and list did not show such a guard on any of the models. The Kemp company was forced out of business by a liability suit around 1990; as a registered owner I received safety stickers and emphatic instructions on safe use. A company named Green Acre Lawn & Garden, also in Litiz, PA, bought and sold the inventory of spare parts that I now believe is long gone.
Admittedly, it is a machine that invites abuse, but my opinion is that it is a homeowner machine. Early on, the 1-1/4" drum shaft broke, the holes in the thin, sheet metal sides elongated, many teeth split, and at fewer than 400 hours, an angle iron on the drum failed with catastrophic results. It is a simple machine and far easier to work on than my neighbor's Troy-Built Chippewa. I welded the shaft back together, hard-faced the teeth, welded reinforcements at the holes, had repaired the drum, replaced the pillow block bearings with larger, greasable ones, and replaced the B&S with a 9.5 HP Kohler. The industrial arts dept. at the school where my son teaches repaired the catastrophic failure of the drum and fabricated a new section of screen for the cost of materials. My son and I now use the machine to shred leaves and chip <2" prunings but use my 6" PTO
chipper for most chipping.
If you can coddle the machine it may last. If it doesn't last, it is easy to repair. You may want to fabricate a shield for the exposed drive belt and pulleys. Good Luck!