Did Shubert and Nederlander ever co-produce

*Shubert

Schubert died in 1828 and Nederlander went into business in 1912 so that would have involved time travel.

If you meant to ask about the Shuberts and the Nederlanders, then yes they have. You can easily search for all of the instances on ibdb.com. Some Like it Hot is an example as I recall.

From 1981, the New York Times:

https://www.nytimes.com/1981/11/29/theater/he-s-the-avis-of-the-theater-world.html

At the moment, all of Mr. Nederlander's Broadway theaters are filled. That is why, in a rare incidence of detente, he produced ''Nicholas Nickleby'' with the rival Shubert Organization. ''I had the rights to it,'' he explains. ''I have a relationship with the Royal Shakespeare Company. I'm on their board. I thought 'Nicholas Nickleby' was one of the greatest things I'd ever seen, but I didn't have a theater for it. The Shuberts had a theater. I produced the Royal Shakespeare Company's 'Sherlock Holmes' with the Shuberts for the same reason. I didn't have a theater to play the show in.''

Gerald Schoenfeld and Bernard Jacobs, who head the Shubert Organization, and Mr. Nederlander are often not on speaking terms. But they were brought together for ''Nicholas Nickleby'' by Miss McCann, who began her career as a factotum in Mr. Nederlander's office and has managed to remain close to both producing organizations. They are charging $100 - the highest in Broadway history - for all seats to ''Nicholas Nickleby,'' a stage adaptation of the Dickens novel that lasts eight and a half hours.

''We won't make any money,'' Mr. Nederlander says in defense of the $100 tickets. ''The show is just too expensive. I think it will break even or lose a little. I said to Bernie Jacobs, 'Not everything is commercial. ''Nickleby'' should be done for the sake of the arts here.' We each put up half of the money, $500,000 each.''

From Michael Riedels first book.

It went on to say that Gerald Schonefeld and James Nederlander were not on speaking terms and had a contempt for each other. Then there was a workshop in Symonton for Sunset Boulevard, where James approached Gerald and said "this **** has to stop, we aren't enemies". Gerald suggested meeting up in a restaurant in mid-town, when producers entered and saw those talking like old friends, they went red and did a 180 degree turn.

Gerald and James, would meet regularly became the firmest of friends and would stay with each other, in their condos in Florida or the Hamptons. This lastest right up until Gerald Schonefeld death.

They agreed never to stand on each other toes, so maybe a clue why they went onto co-produce.