Look at the last 3 digits of the casting number, 741, 742, 489 = 8-3/4. A 9-1/4 is a Dana, a completely different animal. It will not have a removable center section. It will have a removable cover on the back side, I'm thinking 12 bolts. I do believe the 8 1/4 will also not have a removable center section though not 100% certain.
Russ