Tricky to scan the actual cassette on this one as it has a clear shell with a reflective grey strip inside, and silver metallic lettering for the text, would probably be better photographed.
There are 11 cassette versions of this album on Discogs, a '68, a '69, two '77's and 7 of these later reissues (none with dates). They all seem to be fairly scarce. There first release using this exact Cat. No. had a black plastic cassette shell (with screws).
This is a fairly scarce tape by the looks of it, there's one on ebay for £30+ (inc postage), and, only 8 people own this on Discogs (including me) and 333 people want it.
There are seven for sale on Discogs ranging from £33 - £79 (inc postage) depending on condition.
(Definitely a "keeper";)