The death date is on the front of the mausoleum; the date of the fire and the rebuild date should all be in your journal/casebook if you looked at all the newspaper clippings you came across in the game. The birth date takes several steps to discover. You must win at a game of checkers with Vinton in the tavern, you may also hit the "skip" button which counts as a win. But if you don’t beat him or hit "skip" you cannot progress. After you win, he will tell you he will have a fax sent to you with info about the manor. Go to the den (where the computer is) and click on the fax, then click on the piece of paper in the fax. The birth date will be in the bottom right of the page and is handwritten. Once you look at the page from the fax, the birth date will be entered in your journal. This is another randomly generated solution. You cannot use the solution from the strategy guide or the walkthrough, you can only use the date given to you by your game. Once you have entered all of the dates (vertically or horizontally only) you must click on the lever on the left of the number board.

I'm sure one is 1812 and the other 1808 and I think the last is 1806. Some think they have 1872 but it is actually 1812. DOB is in 17**