It's a milled Haenel Schmeisser made magazine. I'm with Tom on this one. Probably DDR made. Most of those had the Ernst Thalmann 2/1001 marking on them.

What's the bottom of the aluminum base of the magazine look like?

Just plane bottom . No markings.

I really would like to positively identify the magazine that came in my gun. The aluminum bottom is plain . No markings no markings on the body either . Thank You.

So what is a CORRECT magazine in an 1938 S/42?

Thanks.

Here is a 1938 magazine on Ebay. I have no connection to this listing.
http://www.ebay.com/itm/WWII-GERMAN-...YAAOSw1DtXFUVl

No way to "positively" identify an unmarked mag!
You have educated guesses.

Tharpo showed you a SE/63 marked mag, go to Simpson's site and look at their scores of magazines, there are many, many SE/63 mags, some as low as $125.