Welcome on this board mld277.
I think I have this one as well. (there are not that many 3LP-SMiLE-with-coloured-vinyl releases I'd imagine...)
A good find. I think it's a late 80-ies (maybe early 90-ies) release. The packaging sounds less familiar though. Although mine als has that cover with the original Frank Holmes drawing on the front and the complete tracklist of all 3 LP's on the back, but it's not a copy on a plain white sleeve, but an original print. All 3 records should have labels on it. And on top of that my sample contains a fold-out poster of the Frank Holmes drawing + a bunch copies of several work-sheets (stapled together) of several SMiLE-songs.
So maybe yours is a rerelease of the original. Could also be an incomplete original with a “new” cover (because the original one got lost/damaged or something like that). Don’t what’s the tracklist on your copy, but if side F (b-side 3rd record) contains Brian’s SMiLE-sessionparty, then we’re talking about the same release.
For additional info,
www.cabinessence.net or
www.cabinessence.net/boots/9002.shtml