Self don't have any data on which manufacturer, but wanted to contribute:
With a decent to-scale sketch of the fuselage and flying surfaces, your model would be very easy to replicate, especially since (I last checked) Brodak, Cox International and Ex Model Engines all had the same replacement plastic engine mount (photo attached). I picked up a couple a few years ago. The advantage to this one is that it will also fit the later Cox non-tank horseshoe back engines, with choke tube removed (it will run fine without).
Given that a number of the legacy engines, OK Cub and a few others with tank including the last Testors Series 9000 (not the earlier front rotary valve with tank mount) use the Cox tank bolt pattern, one is not limited to Cox only with the mount.
Plane I show is the Goldberg profile Swordsman 18 with an OK Cub .049 and Testors 9000 .049, which were direct bolt in swap replacements for the Cox .049 Babe Bee (not shown). The Swordsman doesn't use a nylon mount, just showing fit.
With an OK Cub or K&B .049 Stallion with tank (I think uses same bolt pattern), you could retain that vintage look to it.
