Thank you very much for the info, epigramophone! And with respect to the authors, I would absolutely buy their book if I could find it, and one day I will, so hopefully no harm done on sharing the info
I'm always open minded to the possibility of collectors or dealers piecing machines together or doing odd things within the last 50 years or so. It's hard to tell sometimes. If it required changing the horn on top of it, I don't know. Possible though, maybe? I also notice that mine does not have a metal plate like a lot of them that state "130A."
The tonearm difference I notice is mostly that the brake tab that comes off the arm has a hole/cutout piece in the 130A variation while the other does not. Is that the only difference between the tonearms, or is one larger, etc.? Does anyone know why the arm was changed? I'm just curious.
When I said the 5B seemed like a common upgrade to me, I don't mean I think people upgraded around 1939. I mean that in the last 50 years I think a lot of gramophones originally equipped with 5As had their reproducers crumble and so people took 5Bs off portable 102s for replacement. I know that nice, solid 5A reproducers exist -- it's just that I've never found one, LOL. I personally think they were of worse pot metal than 5Bs--and yet still better pot metal than whatever Victor was using!