RWTF, if I am understanding your description correctly, the bottom of the barrels lugs, closest to the breech have 51 over XX stamped. Do you mean XX or can you just not read the number.
Those numbers should be read with a 3 in front (i.e. 351) and refer to the pellet count when Remington test fired the gun and confirmed choke. My 1907 production 1894 reads 345 over 328 and my 1900 reads 42 over 38 with the 3 having been dropped.
The P is thought to refer to Remington proof.
The LAEY is a bit of a mystery, as are any slash marks - ///
