no, it's confirmed bullshit, the uranium is buried under a mountain of rubble and the equipment brought with the special forces (2 MC-130Js worth and ~100 soldiers) is not enough to retrieve anything. There are several tons of uranium buried under the mountain. Any operation to retrieve tons of buried uranium would require dozens of heavy vehicles and weeks to carry out.

the narrative exists for Iranian propaganda purposes because if you look at what happened (US forces set up a forward-operating-base deep within Iranian territory, held it for hours, found the airman, then left without casualties) it's very embarrassing for the Iranians.

According to multiple sources, the uranium of interest is under 500 kgs and easily transported using relatively light motor vehicles. Ted Postol of MIT has done multiple interviews explaining how it would have been managed.

Iran could have easily scattered the material over multiple locations well before the US/Israel hit the site.

Having said that, I find it incomprehensible that if Iran had the material, they didn't finish the task of building a working weapon. If you have resources the US wants to steal, and you have no nukes, you get attacked.