Please go down and look in the "name that part" section. The middle image in Handy Andy's post shows the exact striker plate I took off of the 1951 Chevy five window pickup I sold. I scratched around with some sandpaper and mine is also stamped L. The lock in Andy's post also matches the 1951 lock I have here.
I think all will agree it isn't the striker plate above. The mounting holes, everything is different. The 1951 striker in the truck I had attached with 4 bolts and had the same adjustment back plate as in the 1952. It just didn't allow for as much side to side adjustment as the 1952 and it was all different. Adjustment in the striker above isn't the same at all.
I have seen that striker plate (above) before, but it was from earlier years. Maybe there was a bastard striker made mid or late-year. And maybe this particular striker only was used in 1951. Take a look below and then go look at the "name that part" post. I promise you this came from an unmolested 1951 truck.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end