IBM 49/50 key with PCB

[Rotti]

So I am putting some serious thought at replacing my Orbweaver with one of the IBM 49/50 key keyboards. The problem is I don't like the feel of M. I would rather keep the Orbweaver.

So with this, is the 4704 banking series the only ones with the pcb style F internals? There are 4 of the layout on eBay right now that look like they are F style plate construction, but they clearly have a membrane in the pics, or are listed as that or just stating 2KRO.

Any info here would be great.