I just did an engine change on my granddaughter's 2014 500L, 1.4 and automatic. While I was swapping the parts form the old engine to the newer used engine I discoverd that the starter has 2 bolts and a dowl that locates the starter. The issue is that the bolt that is up top comes form INSIDE the bell housing requiring the trans or the engine to be pulled out to get to the bolt. Not sure how any engineer thought this was a good idea.
Since I had the engine sitting on a stand I drilled out the boss on the inside of the bell housing/adapter plate to a size where I could force a nut in with JB Weld on it and installed a bolt with a small enough diameter that it easily goes through the threaded hole on the starter.
With the lower bolt and the dowl the starter is properly located and if we ever have to change the starter the top bolt has a 12 mm head on it.