Couple years ago I bought a C77 main set 455 std/std and it was just as described above. I called Clevite and they verified it to be correct as per their BOM. Said that it's a fair debate among performance enthusiasts as to whether the lower half should or should not be grooved.
Summer 2002 bought a FM std/std set for use instead of the C77 because personally I plan to put hundreds of thousands of miles on this engine and don't want to be kicking my own a$$ at 200k when the oil light is flickering in summer idling in gear and wondering if it's my grooved lower #4 worn into crank excessively. The FM set had grooved lower for only the #5 bearing and I liked that bette for this engine so I used the FM set. the #5 is so much wider than the rest anyway so maybe it's not as much of a biggie to have grooved lower on that one.
BTW, on the rods, I noticed the C77 std/std set might have been must a hair looser than the FM rod set. Just FWIW in case you have a crank that has slight variance in the journal diameters and the two different brands of bearings might help calibrate that out.
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