Yes the firing pin retainers without slots are pins, not screws. On mine, from one in the 46K range & up all have the pins. From one in the 42K range & down they all have screws. Considering we are speaking of Lefevers I have no doubt there are exceptions to this. Also, all from the 46k one & down have fluted combs, but none like this one. On my guns the "Root" of the flute is essentially parallel to the top comb line. Looks like the same engraving pattern as on my FE SN 38025.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra