The way it usually works off the top of my head for apple stuff is how long has it been on the market, how well is it selling, what the competition has to offer, and what retailers will be selling it. If you look at the iphone, up till about a couple years ago there was no discount during black friday. the iPhone was dominating sales and apple wasn't having a hard time reaching higher and higher sales figures. In order to combat this once the iphone market started to plateau you saw more retailers selling them and for bigger discounts during black friday. It also helps that the iphone is such a household name now that its what you want to advertise in order to bring in customers. The apple watch which was on the market for a few months and was selling well but not what apple had predicted saw more retailers starting to carry it and big discounts during black friday.
Now with the MacBook pro launching in the middle of the holiday season my guess is no discounts since there is enough initial demand to hold it over. With apple showing 4-6 weeks for delivery 3rd party retailers are going to have a hard time getting them and therefore will not be discounting. One thing I can see happening is maybe 100-200 dollars off depending on the model but this will be in line with educational discounts which apple already has. I would say if you want a new MacBook pro get it now or wait till about february or march of next year to see prices drop and they will for sure drop by this time next year. Apple did that with the retina MacBook pro and rumors are they will be doing the same with this one.