Ich hatte wegen der Frage des Zielschleppers mal bei einem rumänischen Kollegen angefragt. Ich stelle mal die Antwort so rein, wie sie gekommen ist. Demnach gab es also solche Maschinen nicht.
First of all, I am not an expert on WW2 Romanian AF.
But according to two sources I have all surviving PZLK.37A/B Los were
destroyed in the autumn of 1944 (the sources are the book Third Axis Fourth Ally by Mark Axworthy, Arms&Armour Press , Modelism 2/1994(article about Los in Romanian service, wrote by a WW2 veteran).
In early 1944 only 8 PZL-37 survived and they were grouped in
Escadrila(squadron) 76, which became part of Grupul 4 Bombardament(4th
bomber group).
Their last combat action took place in early May 1944. Due to the low
serviceability of the aircraft, on May 7 is decided to retire all Los from
operational service and to disband Escadrila 76. All flyable aircraft were
put in storage on Campia Turzii airfield ( west of Romania, near Cluj). The
aicraft were destroyed, together with all aircraft stored on this airfield
during the combats in the area in autumn 1944 between the German forces and the allied Romanian and Soviet forces.
So they could not serve as target tugs in 1946! In any case, there is no
evidence of being used in such destination.
The aircraft were old and with low serviceability (lack of spare parts and
technical support, 22 aircraft came as refugees from Poland in 1939 and were
introduced in Romanian service with nos from 201 to 222; the same isituation
was with PZL-23 Karas). There is photo evidence that at the level of 1948,
the more reliable JRS-79B were used by reomanian firemen for fire training,
the only from the bombers used in Romania during WW2 which had a longer
career after the war was He-111.
Another German aircraft which survived quite long after the war was
Ju-52/3m.
But the postwar period is the darkest from the Romanian AF history, there
is little photographic evidence.
Related to photos, I identified two photos on Rumanian Air Force The Prime
Decade 1938-1947, Squadron Signal Publication 1999.
But in a different book it is stated that on December 1944 two aircraft took
part on a composite bombing raid against german forces in Slovakia, while in
Romanian aeronautics in WW2 edited by Modelism International in 2003 it is
said that aircraft no.211 survived on Turda/ Campia Turzii till May 1945.
But I personaly do not rely on these sources.
I hope that my reply clarifies a little bit this subject.
For a more documented and authorised reply I passed this question to a
Romanian historian and I will wait for his reply.