I suppose I don't know for certain, but it seems like a fairly safe assumption. There are a few similar cases where the book quotes a catalogue number corresponding to an earlier release by the same artist, rather than the record that had been just issued. I get the general impression that catalogue numbers were not part of the original data (or at least hadn't always been noted down), and instead were added in at a later stage.
You're right in thinking that re-entries were fairly uncommon. There were only around 50 or so records (out of 2326) that meaningfully re-entered the charts from 1940-52 (as opposed to just dropping out for a week). The reason for the re-entry is usually due to a new recording being released by another artist causing the song to regain popularity. This often happened in the early to mid forties, since it would often take three or four months for recordings by US artists to be released in the UK.

The strangest re-entry I've found is that of Nat Gonella's recording of "Juanita" on Columbia FB-2503. This initially charted for two weeks in Nov-40, but re-entered for a month in Mar-43. The reason for this appeared to be a new recording by Monte Rey on Columbia FB-2902 which charted in Mar-43, but it turns out that this version of "Juanita" is an entirely different song! Either it's a complete co-incidence or someone's got confused somewhere!