2004 Sportsman 500 HO rear CV Boot

Hey Folks, My sportsman 500 HO, buy the manual: has an early style and a Late style type of Bike. I see on line when I look for replacement Rear outer CC boots that there are two different part #'s P1000 and P1001. The only difference I see is the life of the boot. Are the rear axles the same and The difference is only the life of the boot or are there two different Trans with different size axles with boots?

some boots are classed as extreme for winter use bought one for my razor they are thicker rubber