Stock 727 out of a 79' B300...

I've decide to leave the valve body for last in my rebuild and upon disassembly and using the ATSG guide as a reference I've noticed that the valve body I have uses a low reverse ball but in the book the picture shows that it's not used in a 727... So why do I have one and could that be the reason I didn't have reverse??

20210614_183430.jpg20210614_183625.jpg