The tan P99 is the airsoft, and is always on the left when you can't tell the color.
The two letters marked on the frame, AA on the real, MZ on the Maruzen, are the dates for production. AA stands for 00, so my P99 was made in 2000. The MZ probably stands for MaruZen.
The Maruzen has almost all the same features of the real P99. Double-action-ish (not sure the exact term) trigger pull on the first round, and a single-action trigger pull for all later rounds. There's also the decocker. When decocked, you have two options, double-action, or you can pull the slide back a little (.25 inch on the Walther, .5 inch on the Maruzen), and the hammer will be cocked for single-action fire, without ejecting the chambered round. Takedown is a little different, but uses the same button.
Walther:
1. Lock slide
2. Pull and hold down the takedown button (it's very, very stiff)
3. Slowly release the slide
4. Pull the trigger to decock (deckocker won't work when the slide isn't aligned)
5. Slide off
Maruzen:
1. Decock
2. Pull and hold down the takedown button (very light)
3. Slide off
The trigger pull on the Maruzen, when in single-action, is very light and smooth. I didn't really bother to compare it to the Walther's.
Of course, the Maruzen is a bit lighter because of the plastic slide (which seems to have a few metal inserts).
I tried attaching a Walther front sight, and it fit, but the allen screw wouldn't secure it. Walther grips should fit nicely as well.
The only off details:
-Missing eagle mark towards the rear of the slide.
-Should have the serial number on the slide under the ejection port.
-Non-functioning chamber indicator
-Manual safety (push in from the right side of the takedown latch)
The kick is more than I expected with Duster. Will try to get a video in the morning--my digital camera's videos suck unless there's a blinding light source.