I was told this was removed from a 2001 K1200LT. I bought it solely for the drive cup to put on a reman'd 50A alternator that I was upgrading on my '92 K75RT (formerly 33A). I have not tested this alternator but have no reason to believe that it doesn't work. All I have done is remove the cup and take some pictures.
On visual inspection, this looks like a very low mile alternator. It's super clean with little corrosion and dirt.
You can donate the case from your worn out 50A to reconfigure this 60A to fit your bike.
Information to modify this 60A unit to be compatible with your 50A mounting:
http://www.motobrick.com/index.php?topic=5231(see info starting at reply #22)
$50/obo + shipping or local pick up in Atlanta (west side).