It's an interesting exercise trying to fit parts off an 85 BX to anything else believe me.
When I bought the Estate, a Tri, it had a dinged front guard and no inner guard. A mate had a Trs so I asked him what he wanted for the guards; "You're welcome to them" I'm told. So up I go, remove from car and carefully pack in the back of the Xantia.
Rip old guard off, refit charcoal canister that was hanging by a bit of fencing wire, go to line up holes and...........whoops; won't fit. Different side repeater (round instead of square), then bumper won't line up, followed by indicator being all different and is in fact (from memory) a bit longer overall.
Try to find a guard off the right model; nobody has one, so eventually I manage to get a mate in Brisbane to negotiate a price $80 on a dinged one. Straighten and fit....you beauty!!!!!

Go to fit inner guard; you guessed it. Won't fit.
By now totally frustrated so take to it with a jigsaw and cut it to shape and fit to subframe using 10mm bolts.............now fall off ya bugga!!
Looks good now, but what a battle royal it was that could have all been saved had I been able to surce the Tri parts straight off.
It's amazing how even cosmetic parts on BXs aren't interchangeable (over here anyway) Tri bumpers and tail lights won't interchange unless they are all done. Estate tail lights are different again as are TZi ones. I don't know if they standardised them more over there, but it really is crazy in a country where some models were sold in very limited numbers. You'd think they would have tried to standardise some of their export models even for their own convenience and stock holdings.
Alan S
By the time you're old enough to know it all, you can't remember why you were learning.