2018 LTZ RPO (U12?) Headlight question

[Lower Buncombe Coachworks]

Hello everyone. 
I've been doing a bit of work on a friends 2018 LTZ and part of it was replacing a headlight. 

Really all we needed was a lens but had no luck finding just that. 

Got a decent deal on an assembly and after installing discovered the replacement was one that required a D5S bulb, which lead me to find that the factory assembly was RPO. 

So at this point, I'm assuming we can put a D5S bulb in there and have light on that side but I am thinking the best thing would be to go through the trouble of removing the lens off the new assembly and transferring to the old one? 
I'm aware what this entails and I'm not looking forward to it, as removing the broken lens off the original assembly was quite a chore. 

Of course, to remove the RPO assembly the lens would have to come off anyway. 

Just checking to confirm that there isn't another option I am not missing here, with the assemblies I have available. 

Thanks!

 

[MikeBMW]

In my experience, the headlight assembly is a total replacement, not just the lens.
There is a bolt for for removing the assembly buried behind the wheel well liner and facing down. It's a bit of a pain to get to.