Hi Archie,
If you booked direct with Disney then you will not be made aware of any special offers or promotions offered at a later date which might include the dates of your stay.
My best advice to you would be to keep checking the
Special Offers section of the Walt Disney World website periodically between now and your trip to see if any offers or promotions are released.
If they are, I would recommend that you contact Disney on (407) W-DISNEY to ask a Cast Member if it is possible to apply the offer/promotion to your existing reservation. If the Resort and room category you have booked is available, you will be able to apply the discount. If it is not available for your specific Resort selection, you can ask about changing to a different room or Resort category. Most times this can be done without any cost to you (and if there is a small change fee, it is usually offset by the amount of the saving)
If you booked through a travel agent, they might make you aware of any newly offered discounts or promotions and you would need to speak to them direct to find out if it would be possible to apply them to your existing reservation.
Wishing you a magical trip filled with memories which will last a lifetime.