Bit late but
Nice to see another with the Octura mount & carb, the water-cooled cylinder with 10mm plug is original, O&R had a part no. for this one, possibly looks repaired where the tubes are attached.
The type 193 is a standard engine supplied by O&R for many uses, Octura bought them & would have supplied all the other parts.
I'm guessing it doesn't have the special Octura rotary valve, nor does mine & believe it or not, the serial number is only two numbers apart from your engine, someone lost the cooling baffles from mine (the plates with the serial/type decal).
Since acquiring mine I have added the Octura carb & an extra noisy open muffler.
David