The RS headlight is attached to a mount that is on the steering tube of the frame. It always points in the direction of the frame and bike. When someone mentions 'ears' they mean the mounting pieces that let the headlight be mounted to the steering forks.
When I got my 'wrecked' R100RS, I removed the faring and then cut the already bent faring mounts ... so that the headlight was still held by the steering tube mount. It worked fine ...
But if you want it to 'look right' ... you'll need a set of 'ears'. They can be had fairly inexpensively from Ebay. There are also aftermarket generic one's that look OK too.
PS - The RS faring also holds the 'ignition key'. This key will need to be moved to the headlight bucket ... and that's where the genuine BMW headlight ears will be handly (because the BMW method (at least for the RS vintage) put the key in the hole created by the bolt connecting the headlight ear to the bucket!).
I did the same thing years ago ... The bike is long gone ... but it was a great learning experience.
On the first (Bike version 2.0) you can see where the key is meant to be on the naked bike. On the side of the headlight bucket.