I believe you are right.
Type 6 Wheel Cover: Mag Type.
Front: F-250/F-350 4WD
E7TZ- 1130-B #3800 Axle Capacity
E7TZ-1130-C #4800 Axle Capacity RB/F0TZ-1130-E
Front/Rear: F-250/F-350 2WD/ Rear 4WD
E7TZ-1130-A : Full Floating RB/ F0TZ-1130-B
E7TZ-1130-F : Semi Floating RB/ F0TZ-1130-C
The Centers do look too narrow for the full floating axles so that would make these:
E7TZ-1130-F - RB/ F0TZ-1130-C; Semi Float rear, with the; E7TZ-1130-B #3800 Axle Front
Good catch Shaun!
Truck: 1981 F-150 Explorer / Engine: 300-6 California MCU Feedback System / Trans: T-18 - 4 speed / 2.75 Ford Rear Axle Open Diff.