[klondike98]

The upper bakelite block appears to be #67 in the diagram (a 3793DG double .015uF capacitor block).  The lower one looks to me like a modification to what is in the schematic and is a bakelite block capacitor that is likely replacing capacitor #57 (a 0.03uF cap).  The bakelite block also has on it a terminal strip that is included in the schematic.  I think you will need to trace out all the connections and components to see how the bakelite block cap is wired up and confirm my speculation.  (I don't have a 37-620 to look at so this is just based on the photos and diagram).  I believe I see the 0.015uF #48 paper cap so the bakelite block doesn't include that one.  Use the schematic to see where the items in the diagram actually are connected (but understand that the schematic shows electrical connections, not necessarily physical locations of the connections)

There is bakelite block cap wiring diagram information in the Phorum tech section.

If you pull the lower block cap out, it will have a number on the side and you can also look up the internal wiring of it, though I also always trace it.  Once in awhile there is a block that is wired up differently than the diagrams.

Here's a thread on how to restuff those bakelite block capacitors. Its not as hard as it looks to restuff them.