BMW brakes sensors setup is L-Front and R-Rear on all their cars.
If you want to double-check the part number for brakes pads, etc. put the last 7 of your car's VIN in here
http://www.realoem.com/bmw/enUS/select and you can locate the components.
You already have experience with the job, but you might check this site for future DIY work procedures; The BMW TIS provides install procedure, look here
https://www.newtis.info/tisv2/a/en/
again, input your car's VIN info then drill down in the brakes.
Good Luck/Bill