Jerry,
Judging by your numbers your gun was probably choked .032 in both barrels originally which would be full and full. The barrels should be black and white not brown and white. The barrels came from the factory looking like the picture posted by Revdocdrew. As posted by researcher nobody seems to know what the Y stands for and my 1900 has it too. I have no idea what the L stands for. How much does it weigh?

So many guns, so little time!