Is my enlistment bonus tied to specific unit and slot?

Typically nonprior service enlistment bonuses are not - only associated with MOS.
Reenlistment bonuses on the other hand usually are and the unit/position will be in the contract.

Read your bonus.
Pretty sure it says something like "Failure to remain in bonus UIC/MOS throughout the entire contract period may result in termination and recoupment of the unearned bonus portion."

However, if your MOS did not change and only the UIC (unit), and you are not excess, then you can get with your AGR and your retention NCO and submit an ETP, explaining that you ended up in another unit through no fault of your own, and likely retain the bonus.