It makes me wonder how many other library albums released in mono were actually recorded in stereo. Anyone?
This album originated as a Teppaz release and according to Discogs was available as a stereo version in 1960. It's unclear what the relationship between De Wolfe and Teppaz actually was but numerous recordings from the one end up with the other. There definitely are anomalous stereo mixes though!
A couple I've noticed -
Sunspots by Derek Laren - released on a 78 in 1962, DW 2752, never reissued on LP, but finally appears in a true stereo mix on B-Movie Monsters in 2000. Either they retained the multi-tracks and remixed it for the occasion (unlikely), or De Wolfe were routinely making stereo mixes of their output throughout the 60s. Which is exciting.
Stormy Weather and
La Rue Morgue - both from DW 2710 in 1961. These were reissued on DWCD 0192 - not finished stereo mixes as such: every instrument is mixed either extreme left or extreme right, so basically they're the original 2-track multitracks. They sound horrible but obviously were never supposed to be heard in this form.
Probably many more examples.