I was checking through deleted revisions in the main namespace by Conversion script on the English Wikipedia, to find old deleted edits to history merge:
I found that in all pages deleted before Wikipedia was upgraded to MediaWiki 1.5 (late June 2005), all edits besides the latest one are corrupt. An undeleted example of these edits can be found above; the edits were previously at the title "Clearwater River, Idaho", and I history merged them to the existing article "Clearwater River(Idaho)". Another example involves the page about Michael Collins:
The edits were previously at the title "Michael Collins (disambiguation)".
Even though 99.9% of the text in these old deleted archives is garbage, the other 0.1% is very important page history and it should not be corrupted.