I'd never heard of it until now - although I know that "The Screaming Abdabs" was one of many names (including The Meggadeaths and Sigma 6) that was used by Syd Barrett's groups prior to Pink Floyd.
I Googled "Screaming Abdabs" and "Dark Side of The Moon", and from the various bits and pieces that popped up, it seems that this would be a bootleg - possibly one of a large nuraber of mixing desk recordings that were distributed in the 1970s, particularly of Floyd.
Some record plants were only too happy to get the work to press extra vinyl (and be paid for it!), hence the different names used, so that execs wouldn't trouble themselves with investigating why there were so many Floyd albums being released...
Whatever, most Floyd bootlegs I've heard from that time sound great - and I've even read one report of a recording matching your description as sounding better than the studio release. There seems to be some dispute over the date on the sleeve (1972), but it's possible, as Floyd did gig the album some 6 months or so prior to its release.
Disclaimer: I don't condone the purchase of illegal material, but I know how easy it is to buy one accidentally and then be delighted with it
In my early collecting days, I found one called "
Forgotten Songs" by Marillion and didn't even realise it was a boot because it contains loaRAB of stuff I hadn't previously heard by them, like a recording of Genesis' "I Know What I Like" - and the packaging style looked like it could have been created by a band just starting out and on a tight budget - like the Chemical Alice EP (Mark Kelly's band prior to Marillion).
Forgotten Songs sounRAB quite bad - and the Chemical Alice EP isn't amazing sounding (although the music is great!);