Owner apparently thought the non-factory vinyl roof was a better investment than replacing the wood grain. https://lasvegas.craigslist.org/cto/d/1977-oldsmobile-wagon/6382176923.html
Also I doubt it has a 454 under the hood, unless it has been swapped out, all the BOP engines larger than a Olds 403 were dead by 1977, and I do not remember BBC's being optional in any US sold Buick, Olds, or Pontiac's (Canadian Pontiac's being an exeption) I agree very unattractive additions to this one.
Is that actually a Vista Cruiser? The seller doesn't call it that. There was both a Cutlass wagon and a Vista Cruiser wagon that year. The standard engine was the Olds 350 with the Olds 403 optional. Yes, the 454 is a Chevy engine, and this car did not come with one originally. Could have been swapped in, though. At least, according to Setting the Pace, there was a non-Vista Cruiser Cutlass wagon for 1977. But the '77 Olds brochure doesn't show it.