99 XJ 8.25 Axel Tag Info

I have a 99 XJ with a 8.25 Chrysler axle with 2 tags bolted to the cover. 1 tag is stamped 3 5, I take it this one is for the ratio (3.55). 2nd tag is tamped 0609 or 0509, tag is very rusty over the second digit. Can anyone tell me what the tags mean????

Thanks Gandolf

Haven't got a clue, other than the axle ratio........our '98 XJ diff tags are 3.5 and 1278. Sorry.