The owners manual that you can get for free from Buellmods.com and Buelltooth.com has a VIN breakdown. Yours should be 4MZWX............for a Scg.
The 'Long' was a whole different bike with a longer frame, swing arm, seat and rails. Someone bolted on the seat rails, pan, and seat to a regular XB9. There were no XB9Ss bikes made, they were all 12's
With just a K&N, I believe you'll be fine without a new fuel map. Good luck on finding the factory race muffler. Look into Drummers, they use a stock can, flow well and sound good. Then you will need a fuel tune. Look at Buelltooth.com to see if they have one for you.
Oil is a very personal thing. Theres plenty of threads to search on the opinions of people here. I personally prefer a synthetic 20w-50 V-twin specific oil and the Harley Formula + for the trans if the clutch is stock. If the clutch is aftermarket, use whatever they recommend.
City light is usually only in Euro bikes. Use the right low wattage bulb or you'll melt the headlight housing.
A RSS is a great, cheap upgrade. Get the whole comfort kit if the heat on your leg bugs you.
Good catch from a loving owner. Now go ride !!!!