Hi John,
I am not near my books, but from memory :
1. The chamber dating on the Navy lugers did not happen until the M1914 run of lugers. Your 1906 Navy with the blank chamber is proper.
2. I think the original lugers all had the hold-open feature but the German army, originally, spec'd it "out" with their design finalization of the P-08 in 1908. Was added back (in 1913 if I recall) and the earlier P-08's were to be arsenal retro-fit with the hold-open...some Bavarian unit lugers never got the retro-fit...
On these retro-fit P-08's, you can usually see the hole drilled through the right side frame where the hold-open is placed (and the "RC" stamping nearby). On your 1906 Navy with its original hold-open, you should not see the "hole" on the exterior of the frame's right side.
p.s. Thanks for the photo of the area under your thumb safety lever...I was just curious to see how they have reworked the area...
Regards,
Pete... <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />