Some thoughts. Like Kev mentioned, the reserve light comes on about 60 miles before you run out, which is longer than most bikes I've ridden. At first I thought it was weird and was going to modify the sensor. But I've come to strongly prefer the 60 mile warning. With a 60 mile warning, I can forget about tracking total mileage since fill up. I can now just ride in peace, until the light comes on, and then I only have to worry about tracking the 60 miles remaining. And a 60 mile warning means you have plenty of warning, even if the light comes on after you passed the last exit 5 miles earlier. Just go to the next one. With only a 30 mile warning, you might be tempted to turn around and go back.
Second, if you or the service guy are going to be at the driveshaft, I would lube them. Personally, I see no reason why it would be better to not lubricate a shaft that is exposed to wear from hammering, rotation, and sliding forces, and also from corrosion and fretting due to moisture. I do not see why a BMW shaft should be lubricated but a Guzzi shaft should not be. Unlike an exposed shaft on a tractor that is admittedly exposed to dust and hay, the shaft on a Guzzi is protected and the grease cannot be contaminated by outside debris.
The swing-arm bearings on my 2013 are a sealed unit. No need to mess with them.
For the first 5,000 miles or so, I suggest you get some blue Locktite and monitor all the nuts and bolts for tightness. They can vibrate loose. In particular, the stop bolt for the rear brake pedal, the single bolts that clamp the gear shift mechanism onto their shafts, and the bolts that hold the side panels on. I've also had the front brake mounting caliper bolts all come loose, as well as the rear passenger peg mounting brackets.
Also monitor the nuts that hold the exhaust header onto the front of the cylinder, as well as the exhaust clamps on the cross-over and the mufflers. Mine would loosen periodically. But don't lock-tite those; instead just cooper anti-sieze on them.
This is where I am with the spline lube thing, too.