[Chas]

I, am not surprised at the value of the choke in detector service. The "audio coupler" in a SW-3 has a very high value choke. Then, again, it is in a different style of detector, grid leak, regenerative.

IMHO the RCA engineers certainly did not "over engineer" the detector circuit and planned for a reasonable fidelity from the radio.

If the choke is iron core and layer/parallel would it is not all that difficult to replicate. An alternative is to hack an interstage or an output transformer primary, by ignoring unused winding or "ripping" it off. If that interstage does not yield enough Henry's, series the primary/secondary.
If the winding is "universal" that can be done with a Morris but with wire that has been waxed... Subbing another "type" of component will not give the results desired. If that were true RCA their bean counters would have done it...

Chas