I think you're right. I think the deal has already been made, they're just waiting for the green light from political leadership.
Saudi Arabia will allow Israeli aircraft to stage through their bases. This tremendously simplifies the problems for Israel in putting together a meaningful sized raid without using virtually their entire air force.
I believe it is also important to the Saudis that they not appear to be merely letting the Israelis use them. (and they're right about that) So I think they will not only allow the Israeli raid to use their bases, they will participate in the raid.
Only in the movies can two disparate air forces coordinate a raid with no prior planning and practice. They can't afford to be seen practicing together, rehearsing etc. So they won't be flying wingman for each other or hitting the same targets. I look for the Israelis to use their attack aircraft and precision weapons for most of the targets that matter, and to provide their own TARCAP. I look for the Saudis to provide a lot of the vital supporting attacks - hitting radar sites, air defense sites, airbases, etc. They'll make the corridor, the Israelis will fly through it. It sends a very strong message to Iran from the Saudis: we're not just letting the Israelis hit you, our beef with you is serious enough we will shed blood, yours and ours. (Kind of like blowing up someone's embassy...)