Wills In The 19th Century...

There may have been a few technical changes to wills and probate, but they are essentially the same as they have been for a few hundred years. If you read a will written in the late 1800's, you probably would just wonder why it was hand-written until you got to the date.

Check out some genealogy books on the subject. There's plenty of material on legal documents that were used. The library should have a few.

Some things I've learned from genealogy (related to wills, but not to the question) that may be useful.

I've noticed that most of the wills of the past were signed within a few days or a month of the person's death. Basically, they became ill, realized it was time, and did the will. Some died intestate--no will, and those also tended to die suddenly. I had one relative who was beaten by another man and died a day later--because of the circumstances of how he died and the suddenness, the town council actually created one for him afterward.

With one of my relatives, it took some time for the will to be probated (believe it was a month or two afterward), and the family had to ask the court for money for the widow.