Some more info about the Rach Pc's 1 and 4 form a poster at another group :
There is also a recording of the original version of the First Concerto on Ondine ODE 977-2 Alexander Ghindin, piano with Ashkenazy conducting the Helsinki PO. The disc also offers the "original" version of the 4th Concerto. I believe that after the composer made a significantly revised version of the First Concerto, he made another version with some slight editorial changes. Hence there are three versions of the First Concerto. As for the 4th Concerto, the version usually performed is the result of what he did for the recording. There is a curious letter the composer wrote to his friend Medtner. My recollection is that Rachmaninoff was commenting on the recently completed 4th saying something like, "it is so long, it would need to be performed in parts over two successive evenings!" That has sparked speculation that even the "original" version is not fully complete.
I should add that the composer made a revision of the 4th Concerto before the revisions he did for the version he recorded. The first revision dates from 1927 and has been recorded by pianist William Black and the Iceland SO conducted by Igor Buketoff [Chandos 8987].
The text below is from an article by Geoffrey Norris. The new Rachmaninoff Edition contains, as I recall, all versions of the 4th Concerto.
"Our plan was that the other three in our group would then have the arduous task of preparing a score and orchestral parts, though in the event this was taken on by Boosey & Hawkes, Rachmaninov's principal publisher. My next job was to find somebody to perform it, and here there was a stroke of luck. Selflessly pursuing my sybaritic brief, I was spending a weekend as a guest of [Alexandre Rachmaninoff] at the Swiss villa that his grandfather built on the shores of Lake Lucerne. Vladimir Ashkenazy, who lives on the other side of the lake, came over for drinks. In conversation it turned out that our Fourth Concerto idea fitted in perfectly with a plan of his own to conduct and record the first version of the First Concerto, with the Helsinki Philharmonic and the pianist Alexander Ghindin. The Fourth would make an ideal coupling. From then on, it was plain sailing, and both concertos were recorded for the Ondine label in Helsinki's Finlandia Hall in March this year. So, why did we decide to set this project in motion? The fact is that the Fourth Concerto has never sounded quite right. The music, particularly in the finale, has a truncated feel to it. And there is good reason why that should be so, because Rachmaninov made hefty cuts to it. The concerto had been germinating in his mind during his last years in Russia, but only after he had emigrated in 1917, and when he needed a new concerto to add to his own repertoire as a pianist, did he sit down and finish it. Immediately, he was alarmed by how long it had become, joking to his friend, the pianist and composer Nikolai Medtner (to whom the concerto is dedicated), that it would have to be performed on consecutive nights, like Wagner's Ring. There is a lobby of opinion - including, it must be admitted, Ashkenazy himself - which reckons that Rachmaninov would have been better advised to discard the finale and write a new one, because the musical material lacks the strength and substance to match a first movement that Ashkenazy regards as a "masterpiece, absolutely wonderful, nothing like he composed before, one of my favourite Rachmaninov movements".
( Bozo: So I guess I've not really heard yet either the 1st or 4th !! )