Hi Robert,
The Dutch luger with the "1928" stamped on the barrel indicates it was replaced by the local GS armory in Indonesia in the yer 1928. Since the tropics can be tough on lugers, many Dutch lugers from Indonesia will have such a replacement.
If you are out there buying $ 11K worth of lugers, you might want to seriously consider a book investment of a few Hundred dollars to build up a luger library...of say 10-15 luger books
There are many luger sellers hoping they run into folks with the right amount of money that do not have books and haven't studied, and so...take the word of the dealer about how rare or how original a luger's finish might be and why their asking price is a "bargain" or a good "investment".
I have always chuckled when some guy offers to sell me a boosted luger and says it would be a great investment...the "investment" is usually on the seller's end who has taken a cheaply priced luger and refurbished it into a rare and factory mint piece. How does the buyer make a sound investment when he over pays for a gun that is not legit and one he would have trouble selling for years to come and may never recoup his money...???
This is only offered as friendly advice to a fellow collector...
Regards,
Pete...