I think this is not a BMS driver as it looks like nothing in their catalog. Also, on the PAP page for this speaker they don't actually state the crossover frequency. The 450hz seems to be with the full-range drivers (Tang Band and Voxativ).
The closest I have found is from Beyma:
https://www.beyma.com/en/products/c/compression-driver/1CD1114FE8/motor-cd-1114fe-8-oh/
https://www.beyma.com/speakers/Fich...s-data-sheet-compression-driver-CD-1114Fe.pdf
The back cover is nearly identical to yours but there are not push buttons and the Beyma is a ferrite magnet and yours looks to be Nd.
This one is even closer in design except it is a 1 inch exit, not 1.4 inch
https://www.beyma.com/en/products/c/compression-driver/1CD11ND8/motor-cd-11nd-8-oh/
https://www.beyma.com/speakers/Fich...ers-data-sheet-compression-driver-CD-11Nd.pdf
Maybe they got a custom driver from Beyma that is a mix of these two? I looked at a lot of other brands and no other are similar for the back cover to yours.
It also fits because PAP says the 1.4 inch compression driver uses polymer and both of these Beymas use PM4, which is a proprietary polymer of Beyma (probably a kind of polyamide).
The good news is that Beyma makes excellent drivers (really excellent).
I am still doubting that my Radian 475pbBe will actually beat my trusty old Beyma CP-350Ti
The CP755Ti is also ridiculously good (if in fact your driver is a Beyma, this would be an upgrade path as they should have similar exit angles, so matching with the horn would be easier).
https://www.beyma.com/speakers/Fich...ers-data-sheet-compression-driver-CP755Ti.pdf
However, it looks like the Re is different so it might impact the crossover somewhat.