Some (1941) Portuguese contact rifles were delivered to the Wehrmacht. Conversely, a small number of 1942/43 dated 98K rifles are reported to have had Portuguese stamps added to them.
With the bluing you show, here it is sometimes called a “plum” color, and on occasion seen circa 1942/43. But then I’m fairly certain I have an (original finish) 1930’s 98K bayonet with some “plum” color, and for sure a 1939 dated P-08 (Luger) that has a “plum” color. Believing it has something more to due with improper temperature control, versus a desired end result
And as for the single pommel Waffenamt. As you mentioned they are fairly common with the late production 1944 Wehrmacht bayonets. But Waffenamts are also seen sometimes with earlier commercial production (but rarely). Having seen similar bayonets. Which is what I would categorize the one you posted without a serial number or maker’s mark, as one of the exceptions to the rule. To be filed away (mentally) for future reference, as we sort out the bits and pieces, trying to reconstruct what the Germans were doing back when they were made.
PS: My compliments for both bayonets.
Historically interesting, and in exceptional condition.
Best Regards, Fred