'Tomorrow Night' was originally recorded in September 1954 at Sun.

This overdub was originally slowed down by 8% when released in 1965 on Elvis For Everyone, presumably to match Elvis' vocals at that time?

On BMG's 1990 CD release of Elvis For Everyone it has 'Tomorrow Night' running at the correct speed it was recorded.

Although shown on some releases as being released in stereo, the overdub on 'Tomorrow Night' has only been released in true mono or electronically created stereo.

There is no information on matrix number SPA4 5389, but as it is from around the time of this overdub session and before the issue of Elvis For Everyone it is possible that it may be for the version of 'Wild In The Country' with overdubbed maracas that appeared on UK pressings of the album, and can also be found on FTD's classic album of Elvis For Everyone.

Another interesting theory is that 'Wild In The Country' with maracas was overdubbed at the same overdub session as 'Santa Lucia' on October 11 1965, and that one of the overdubbed or extended versions of 'Santa Lucia' may have been intended for the UK issue of Elvis For Everyone too.

As the master tape does not exist in the vaults at RCA in the US, a more interesting theory, and a lot lore more likely, is that 'Wild In The Country' with maracas was overdubbed in London by Decca, in early 1965, unbeknownst to RCA in the US, and was used on the UK pressing of the album Elvis For Everyone by RCA UK. The UK version of the album replaced 'Summer Kisses, Winter Tears' with 'Wild In The Country', as 'Summer Kisses, Winter Tears' had only just been released in the UK on the album Flaming Star & Summer Kisses. The UK release of Elvis For Everyone also had a completely different cover to the US equivalent. The version of 'Wild In The Country' here is basically the mono master (even though RCA in the US had the true stereo master), but it has maracas overdubbed in the right channel, thus making it stereo! It appears that Decca had form in doing this sort of thing at that time, as it had also done this with mono recordings by Van Morrison's group Them, as well as others, where they added maracas in one channel, making them stereo recordings.

In March of 2007, Sony decided to go through all of Elvis' masters. They retransferred everything and remastered all tracks including repairing as many clicks, pops, bad edits and dropouts as they could. They have used these newly mastered recordings on their new releases since 2007 including budget soundtracks, Legacy releases, the 30 disc Complete Elvis Presley Masters collection and the Franklin Mint package.

The new remaster of 'Tomorrow Night' on disc 28 of Sony's Complete Elvis Presley Masters collection and the Franklin Mint set has a note clipped from the beginning of the song and is in electronic stereo. The 2007 remaster is not clipped and is in mono on the 2010 iTunes download of the Elvis For Everyone album and the 2012 reissue of Elvis For Everyone as part of the Perfect Elvis Presley Collection set of 20 CD's housed in cardboard sleeves. These 2007 remasters were not used on FTD's A Boy From Tupelo, the masters were all remastered again from scratch on that set.

Incidentally, 'He'll Have To Go' (SPA4 2332), originally recorded by Jim Reeves in 1959, and released in 1960, was also overdubbed with a new backing track during this session. (NB. Reeves was killed in an air crash in July 1964.)
This overdubbed version of 'He'll Have To Go' was used for the opening and closing tracks of the album Yours Sincerely (LSP 3709) in 1966.

Thanks to Michael Cavino for pointing out the 2007 remaster of 'Tomorrow Night' being released in full on iTunes.

Thanks to Kevan Budd for the theory about the overdubbed 'Wild In The Country' and 'Santa Lucia' possibly being from the same session.

Thanks to David Jull for information on the possible Decca recording of 'Wild In The Country'.