The term "Cinder Block" is a catch all term for concrete masonry units (CMU). Cinder Blocks had problems because of the iron particles in the aggregate they were made with (coal residue or cinders from the steel manufacturing process). Moisture would attack the iron particles, which would cause corrosion, expansion, and deterioration. Some folks also called those "Pop Blocks" because aggregate busting out of the block would actually cause popping sounds.
In the 1950's, Cinder Block was replaced by Concrete Block which didn't have the same issues. To this day people still call CMU's "cinder blocks" ... but that's not really true because they are not made with the same cinders any more (this is like like calling modern day AC or MC cable "BX").
The fact is that most CMU's nowadays are made of concrete. They are mostly used in foundations or commercial applications.
The corrosive effects that you are talking about occur with pure cinder fill (as used under slabs or other groundwork). Cinder fill slightly caustic when mixed directly with water. As for the application that you are talking about, there is really no increased corrosion issue even if an old cinder block gets wet. This is due to the fact that the cinder block would be primarily concrete. Sometimes concrete efflorescence is confused for corrosion, when in fact it has to do with other concrete issues.
With that being said, if you can strap MC to a poured concrete surface in a dry location, you certainly could do it with a concrete block surface.
