I assume you are referring to the current Stella (2008 - now) as you reference gray handle and "XG". The dead give away is there should be a serial number on the reel foot where it states the model(on JDM models) amongst all the cosmetic differences. Yes you are corret that PGs will state PG on the reel foot as well, same goes for XG and HG. You should also be able to easily tell by winding as there is a significant difference in ratio between PG and XG. Try high speed spinning a heavy metal and see how fast you need to wind. If you get tired after 10 casts then its a PG for sure!
Dont know where you are based but the closest Shimano office should be able to quote and insert new gears for you. Wont be cheap and i dont think that will be done within your timeframe unless you take it there in person and wait.
There are differences between the JDM and export more so in models 4000 - 8000. The JDM market offers a wider variety of sizes. I liken a JDM stella to a base custom rod, same blank, subtle differences, and not as common ex Japan.
I personally didnt want to ask this question that has popped up all over the internet so i took the liberty of just buying all JDM stellas. The amount of time spent reading and researching would have cost me well over $200. Thats just my 2 cents.
