You're right. That's my fault.
They do not make a 372XP 52mm. They are aftermarket top end kits. This is also my fault for not doing my due diligence.
Up until a week ago, I was under the impression that there was a 372XP 50mm and 372XP 52mm. I was recently aware that these big bore kits aren't OEM (such as you can't buy a 52mm 372XP Husq off the shelf) I contacted someone about my 372XP build and he corrected me and said 372 is a 50mm, and the XP is 52mm. Now me trusting the guy I said hmm, that makes sense? Weird I haven't found this straight forward difference. It appears I was right originally, believed someone else and didn't bother checking, and here we are today