Bolt carrier, cam pin, firing pin retaining pin, gas key, gas key bolts, and staking are the same. Gas rings on the bolt itself are the same.
Bolts are different. The 5.45 x 39 needs the larger faced bolt but does not use the same bolt as the 7.62 x 39
The 5.56 bolt face is smaller than the 5.45 x 39 bolt face.