LaPlant-Choate Hydraulic pump info

I've got a LaPlant-Choate hydraulic pump I think is off a D2or D4.  It's got a single shuttle valve.  I've got it apart and cleaned up and I'd like to find some info on it.  The metal tag is gone. No idea what the model number is. Looking for a parts break-down.  I think that it's missing a spring or two.  Please see the photos attached.  Many thanks! [attachment=65383]20211118_165224_resized.jpg[/attachment] [attachment=65384]20211118_165237_resized.jpg[/attachment]

Must be an ancient model...not shown in my 1946 LaPlant Choate Technical Manual.

Or could be a later one? My 1947 6U D4 had that style pump.