It's interesting (?) how Berns was able to recycle what was essentially only two albums' worth of material and milk it for so long. Many years ago I put some effort into figuring out exactly what he recorded for Bang Records and attempted to buy the minimal amount that I could. Turns out the 2-LP anthology Double Gold had everything except his cover of "Hanky Panky." Not the best of cover versions, but the completist in me wanted to get it all into one place (which at the time was a CD), and I had that on another Bang LP, Greatest Hits. There are also mono and stereo versions of his albums but I only opted for stereo. The stereo versions are a mix of genuine stereo and fake stereo.Short version: Bert Berns, who owned Bang records, flooded the market with Neil's old stuff when Neil went to Uni. Some of it he tinkered with.
I just found that there was a Complete Bang Recordings CD from 1994, released on Bang Records (zombie label?). Who knows if it's legit or not? It does have a UPC code though.
I do know he recorded a new version for Uni and yes, various versions tend to kind of blur together after a while.I could never figure out the various versions of the song "Shilo".