Could you first tell what color the ring has and the colour of the animal? Also check if it has been paintet several times with various colours. Do I see yellow and white? Is the light feld-grau only due to that the white has eroded?
When it was found in Norway in 1975, it had the same Hare at the rear. I remember the Hare being blue, but that was most likely wrong. When the white colour fades away, the background looks blue just like on your image, and that may have confused me. I cannot remember anything about the ring right now, but I have a drawing of the sign. From the type of vehicle, the way it was equipped and the above document, it probably belonged to the Nebelwerfer Batterie 224 of the XXXVI. (Geb.) Armeekorps. This unit not was stationed in Norway during the WWII as far as I know, but it was at least at the middle part of Finnland fighting the russians. Where the Nebelwerfer Batterie 224 was stationed, I don't know. Parts of it may even have been used among the XIX. (Geb.) Armeekorps at the Murmansk/Liza front. It could make sense that an Entgiftungskompanie were part of a Nebelwerfer Batterie.
How do you know that your vehicle was part of an Entgiftungs-Kompanie?
It could be the ring was blue , than a light blue , can't see it very clearly anymore . That it never was stationed in Norway is possible , but a lot of vehicles where left in north Norway when they retreathed from Russia , so it could be they made the journey from Finnland/ Russia to Norway .
The other mudguard has the Entgiftungs sign as an artillery sign wich i can't see clearly anymore .
When the hair has a blue ring it could be the sign next to the Entgiftung is for a Mörser Abteilung ? Did nothing yet at the mudguards , they are very dented but in perfect condition , will be a few years before i need them !!
It is well known that all the german troops in Finland widtdrew into Norway and were mixed and stationed everywhere. But then the war was practically over in the North and I have never regarded that period as war-like. The troops were mostly like in reserve.
What you call artillery sign is normally called a tactical sign. To the right of it there is written ?./103 or alike. You probably will see it better right off the fender. If you spray on some 5-56 and wipe it off, you may see more details. Since it is written ?./103 to the right of the square, ? would be the Kompanie. In this case the left "wall" of the square should be double (fat) line. I doubt that an Entgiftungs-unit was part of a Mörser Batterie. But anyway, to be sure, you must look for a sign atop the square. That will most likely tell you all.
20.AOK(geb) is a decent possibility, since they did in fact retreat through Norway, but so did AOK Norwegen and AOK Lappland. Then, too, it could have belonged to an outfit actually stationed in Norway.
The hare is a good fit, but I'd recommend visiting Christoph's site, www.wwiidaybyday.com/ Go to the Truppenkenzeichen link. You might find something even closer there.