Can rust be removed from inside chassis rail

Battery decided to spill its guts and has leaked battery acid into the chassis rail causing the protective coating to peel away and its starting to rust. Question is can this be properly fixed? I was planning on removing the engine and getting the bay sprayed anyway and am thinking it might be accessible from the very front of the rails with the front end off?

yes....
professional rustproofers use the original drain/stamping holes in chassis rails
(or make their own) before inserting long spray nozzles to apply their respective
rust proofing

Thanks Smitty that's good to know. Plan was to stroke the ls3 to 416ci for boost in the future but looks like ill have to get this sooner since the engine is out