Do I have a chance contesting this will?

Here’s my story.

My husband passed away recently. In his Will he left me the house ($700,000) and $250,000 dollars. While we were together he managed to put $780,000 into RRSP’s in my name and named me as the beneficiary of a $130,000 life insurance policy. This is all the Will states I am to receive.

He also has his business, he valued at $11,000,000 dollars. He left the business to his 4 sons.

The 4 sons had the business appraised at $7,000,000. They are saying their farther was way off when calculation the value of his business. Inside the business and additional to the value of the business there is $2,000,000 in investments.

They tell me that with the business valued at $11,000,000, it looked like my husband was trying to leave me 20% of his estate. They are also telling me that with the business only worth $7,000,000, that 20% of his actual worth would not include he $750,000 in GIC’s.

The tax implications for my husband’s death are $1,300,000 in personal tax, and if the business was sold the day he died, there would be an additional $1,300,000 in corporate tax to be paid.

In a safe in my house I found a work sheet he had been working on. On it he has my name beside an additional $750,000 worth of GIC’s.

I was never married to my husband, but figure after 19 years of being together, it’s the same. I did sign a Prenup before I moved in with him 18 years ago.

Here’s my question.
Does the Worksheet have any merit? With this, do I have a chance to contest the Will and receive the additional GIC’s?

Thanks for your help.