Along with a digital camera, and exploded mechanical drawings, cameras are also a series of sub-assemblies. You'll see distinct piles of parts, or separate boxes or bins, on many repair benches.
Rollei had a very nice habit of using distinct screws in sub-assemblies. So screws that hold a side panel in place will not hold a focus hood in, etc. Varying diameter, threading, head design, etc. It's almost difficult to put the wrong screw in somewhere. And then parts have ways of 'telling you.' Notches for springs, etc,
Yes, the chassis is an aluminum casting that was machined. Not made by Rollei; I think there are at least two supplier names to be found inside over time and models. Here's a photo of a setup to index and drill/tap both sides of the chassis block after machining.
View attachment 410273
And more factory photos-
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