Could Ultegra and 105 cassette sprockets be interchangeable?

I was cleaning my Ultegra cassettes before installing it in a new wheel, and noticed a crack on the plastic part that holds the 21t and 19t sprockets. I have a spare 105 cassette, could I use those two sprockets from the 105 with the rest of the Ultegra cassette? They’re both 11s.