1966 C10 no suffix code on V8 motor. Different format. Targetmaster???

[cgrocen]

I just bought a 1966 C10, which I believe originally had a 283 in front of the Powerglide. This V8 motor does not have the usual format suffix code on the pad just in front of the passenger cylinder head that is used to identify these motors. Instead it has a code of "TV256250". Is this a replacement Targetmaster motor? The motor is still in the truck and I cannot view the casting number on the back of the block. Does anyone have any idea about what this stamping refers to? See photo. Thanks!