It's difficult responding to questions like this one without knowing the contract with the owner, and the terms of the bid documents. If we are speaking of a set of finished drawings and specs, and if the bidders are to detail the rebar, the bidders should do their own estimates. Most of the estimating managers can quickly calculate volume and the number of lbs/CuYd for the reinforcing very accurately as a check. I wouldn't give them anything they can blame for a mistake.
On the other hand, if it is a fast track job where you ask for bids on incomplete drawings, based on your quantity and degree of difficulty estimates, you must provide the numbers. But then, when the real numbers are known they are change ordered into the contract and the contract cost updated .
Michael.
Timing has a lot to do with the outcome of a rain dance.