According to the info I have (from an LMC catalog), the plant code letter (P) wasn't used until 52-55 model years. Also Bill's link says the same thing.
But the serial of 24831 is lower than the 1952 Pontiac plant range of 28736-49333 for 1952 production.

So that says it's a 1951, but the color of your gauge cluster says 1952 or later according to Jim Carter (but that could be wrong).