I think they do!

Jaden and Jewelina give TONS of kisses, Jaden will actually kiss on command, if I say "give mommy kisses" he goes nuts and his tail is wagging a million miles a second! He also gives me TONS of kisses before bed too and if I kiss either one of them they will start kissing me so I do think they know that it is love and their "kisses" are their way of showing their love for you and for each other.