Last Supper, The (Andy Warhol) Easter Egg - Diabolic Reference?

Warhol uses to insert commercial items in his works of art, to show how art is now available to common people too. In his view of the Last Supper by Da Vinci, he drew by himself the icon of Christ and added famous motorcycles and also a big, red and yellow price. See the numbers in it: 6.99, and Warhol didn't specificate "dollars". Now try tho overturn the last two digits: 666. Warhol chose exactly 6.99. Is it an implicit diabolic reference?