Moin!

LH recognises *G so if you are United Gold or better you get Lounge access and priority boarding, and on checkin can also select exit row seats if they are still available. Lately on one ticket I could not add my Milageplus number to my ticket on the LH website, but had to wait until checkin process. Was able to do it then and my boarding pass was printed with UA*G which allowed lounge access and priority boarding. Don't expect more. The times where I got an op up as 1K on LH are long gone.

So long
-Ralf