Replacement headlight 2012 focus st3

[David-zrgaz]

I need to replace the drivers side head light unit and appear to have dropped down an ebay rabbit hole of part numbers. It's for a 2012 focus st and the part number written on the sticker on the headlight unit is bm51-13d154-hc
This I believe is ford finis number 1856838.
All the searches appear to find the part number but the last 2 digits are different, I.e bm, ka etc. I have tried to find out if this makes a difference and the information I've found is a bit contradictory. Some say yes, some no.
Has anyone else been in this position? Does it have to be the exact part number?
Thanks for any help.

[vw_99]

bm51-13d154-hc

That part number will have started with HA at the end and every time the part is modified or changed in any way it will go HA,HB,HC,HD etc.

The H is the important part others with other letter will mean a differant style.