Bchr Blow Filler Sheaffer Pen With A Junior Nib?

[Vindiction]

Hi all. I recently acquired a vintage BCHR pen on which the imprint has been worn clean away and which has a rather unique combination of elements I've never seen before. Firstly, it isn't a lever fuller as it has a hole in the back, which seems to indicate that it was either originally made as a blow filler or modified into one (though the hole looks very well-machined), yet the section unscrews like it would on an eyedropper. The pen also has a slip fit cap rather than a threaded one, and it's fitted with a nib marked "Sheaffer Junior, Made in USA". Is there any way of possibly identifying which Sheaffer model it might be, or how old it is? I'll try to link pictures of the pen as soon as possible if it helps.

[doggle2]

Probably not a Sheaffer, more likely someone just swapped a Sheaffer nib into another brands pen.