In the beginning Arthur calls Doug to show him something "for men's eyes only". Before leaving the kitchen for the living room Doug holds a filled ice cone. When entering the living room in the next shot the cone is empty.
After Doug attempts to cash the check at the bank unsuccessfully (because it was more than a year after the date on the check), he and Carrie decide to plant it back in the gravy boat and pretend to discover it ostensibly for the first time. When the check is pulled out of the gravy boat, however, it clearly has no endorsement on the back, which presumably would have been necessary when Doug gave it to the bank teller to cash.
It is unimaginable that anyone would write a check for $1,500 as a gift for someone, that would go for over a year (or years) not being cashed, and not be detected through their bank balances by the issuer of check.