to answer the rest of your question. if you want a 'finding of c&r eligibility on a piec enot listed , or covered, you can contact the atf. IE.. you may get a collectors item classigfied as C&R due to some special status..e tc. that info is in the pdf manual i linked you to. however.. in general.. if it's listed.. you are fine.
page 31 of the pdf has the walther listing half way down the page
page 11, just a paragraph down from the top covers 'wanting a determination' if you should need one on some piece.. etc..