I would like to elaborate on a “no” answer.
While not everyone in Heaven will have been Catholic, once everyone makes it to Heaven they will BE Catholic.
Nothing that is not perfect will enter heaven. Therefore, we are purified in Purgatory prior to entering Heaven. Those who have not gone to hell, but are not yet ready for Heaven, will be made ready through purification in Purgatory. That includes belief in Christ’s One True Faith through His Catholic Church. So - should a Protestant make it to Purgatory, they will be Catholic by the time they enter Heaven, because any non-perfect beliefs (such as Sola Scriptura, Rapture, etc.) will be changed in their heart and they will be made perfect. And perfection is (but not exclusively) belief and agreement with all the teachings of the Catholic Faith.
So - while the joke can be seen as anti-Catholic and nasty by some, I personally see it as more accurate and true than most would like to admit, in the politically correct society we live in.