Elvis' stage shows in 1977 mirrored his personal life and his health in general in that they were up and down sometimes good, average or sometimes poor.
Elvis' penultimate tour which ran from 20 May until 2 June was average at best and during his show in Baltimore on 29 May he left the stage and left the band and background singers alone to do pretty much whatever they wanted. After almost half an hour Elvis returned and closed the show around fifteen minutes later.
One of the fans in attendance remarked "After the finale there were no standing ovations , and fans walked out of the coliseum shaking their heads in disbelief."
The show in Largo, Maryland on 22 May 1977 falls into the average and routine category. Luckily some of that show has been filmed by an audience member and was released on Boxcar's wonderful Final Curtain.
An audience recording of the show was first released unofficially in 1994 on an album called "Tonight , 8:30 p.m...." on the JR Productions label. Here with audio from Straight Arrow's newly released audio of the show together with that 'Final Curtain' footage you can decide on the show's merits for yourself.