Thanks Rockin'!

For what it's worth... (as in what-it's-worth?)...

The dealer says it is an F150 and so I went ahead and decoded the Vin at Decodethis.com (one of the only sites that seems to correctly decode a pre-1982 truck) and found that it does indeed appear to be an F150, not F100.

Here are the results:
VIN 1FTEF15F8BPA79306 VALID
Year 1981
Make Ford
Model F-Series Pickup
Engine Type 8 Cylinder Engine
Style 2WD F-150 Reg Cab
Engine Size 5.0L/302 CID
Towing 6,001 - 10,000
Fleet Only No