Just have a quick question regarding using UA SWU on LH operated but CA-codeshare flight.

I'm planning on purchasing a one-way MUC-PEK ticket with CA since it's a lot cheaper than a Y-fare with LH. However, I noticed that the booking class seems to be either L or K. Technically UA SWU cannot be used on X, I, R, N, W, S and E booking classes, but as far as I'm aware, L and K are below W. Does this mean I wouldn't be able to upgrade? Also, is it even possible upgrading a CA-codeshare flight? Seems that most people's experiences are with UA-codeshares only.

Thanks.