In looking at the 1965 Master Parts Catalog, the Service Part Number was C3OZ-9A589-B. The 1960-68 MPC shows this part as C3OZ-9A589-C. The July, 1965 Ford OSI Catalog shows that the C3OZ-9A589-B was replaced by the C3OZ-9A589-C. This means that the parts were basically the same, but some minor change was made between January of 1965 and July of 1965.
Note that the Part Numbers noted above are Service Part Numbers, not the numbers that would be cast into the parts themselves. The cast numbers would most likely be similar, like C3OE-9A589-B. Thus, if the two spacers you have contain the same casting numbers, other than the suffixes, either could be correct, depending on when your car was built, versus when the change of the part was made.
What are the numbers cast into your spacers ?
Bob