[1000mp] Filter Identification

[Larry Dajnowski]

Purchased what I thought was a YF-115C 500hz Collins Mechanical Filter
and installed it in a FT-1000MP MK V (not field) and it worked just fine.

I removed it from the MK V and sold it to another Ham and he tells me
it is a XF-115C filter and not the YF model.

What is the difference between the XF and YF models of this
Yaesu 500hz Collins Mechanical Filter.
Some hits on the Internet show they are the same.

Thanks for any help on this.

73, Larry AJ2W