Yes, you will have to pay the $499.29 but at the end of January, it will be a bit more on top of it. I believe you have to pay the additional $30 by putting the $500 on a flex plan, plus interest. So when January comes, I'd say you'll be looking at least $540 by January, in which you owe.
But don't fret, that 40% from the $15,480 plus possible bursaries will cover that and whatever is left over goes to you. You can use that to pay down your OSAP debt or to buy some Christmas presents for yourself.
If your scholarships (congratulations for getting one by the way!) are already deducted from your tuition, I am almost certain $499.29 is the only thing you owe to McMaster. If this still confuses you, I suggest you to the Financial Aid office in Gilmour Hall and get the answers you seek for.
I want to point out from my previous post again, if you pay the tuition in full. You will get the entire 40%. That's $6,192 rather than $5,652 when the $540 is deducted off the 40%. In short, you pretty much save some bit of money.
Hope this helps!