Question for Kawboy re Mechanical Seal

Apologize in advance because this question is related to the water pump mechanical Seal in a Vulcan VN1500 (not a Z1300).

I'm having difficulty getting a mechanical seal for a VN1500.  I ordered an OEM replacement from Kawasaki but it's only the half of the seal that presses into the block.  The ceramic part of the seal that presses into the impeller is not included and nobody a Kawasaki seems to know how to order that part of the seal.  So, I ordered a generic Amazon seal that was supposed to fit a VN1500 - of course it doesn't fit - it's too big - but the ceramic half of the seal is the right size for a VN1500 impeller.  I was under the impression these seals were supposed to be matched pairs, but since there's not such thing for an OEM seal in this case, I'm wondering if it would be violating any laws of nature if I used the block part of the OEM seal along with the generic ceramic part?  Any thoughts?