Doug,
Thanks for the additional pictures. To some up, here is what you have:
The receiver is most likely from a commercial-range Luger numbered 50358, c/BUG proofed. The breechblock and front toggle are most likely mated to the receiver. It is not possible to determine whether it is from a 1906 Commercial or a P-08 Commercial; there are no physical ways to distinguish them and it position in the serial number range is ambiguous. (you have already noted that the rear toggle is mismatched).
The two e/6 stamps on the barrel suggest that this barrel was inspected after manufacture at Simson, and inspected again after its installation into the receiver. The strange-looking stamp on the upper right of the barrel is understandable if you turn it 90 degrees,
it is the eagle recorded by Costanzo, #148, p.109. I suggest that his interpretation is in error as the e/6 inspector stamps imply that this barrel is new-maufactured; it is in the position commonly used for power-proof stamps.
The frame is from a post-1914 Luger. Chances are that it is an i suffix Alphabet Commercial, but this is speculation. The takedown lever and trigger plate are from an un-determinable source.
The firing pin is the fluted, Mauser-style, and would have been a replacement after 1934.
I don't have much to say about the magazines; however, under the circumstances, I might be tempted to take them at face value.
So, at some price, this rig of Luger, two likely matching magazines, and holster, with a frankly really neat set of unit marks, is a terrific example of the practices involved in re-arming Weimar Germany. You have already noted its overall condition.
Is this the Luger you want to pay $1,600 for?
Hope this has all been useful.
--Dwight