Are you referring to the "altissimo ranges" as flagolett?
They do have a much different sound. Really anything into the palm keys, above high C# in instrument key, has a different timbre entirely. No need to stray away from them though....that's the reality of the horns. If they sound to pristine...they don't sound real.
All the modern saxophones should cover the identical span between instrument Low Bb to High F# (or F on some old models high G on some newer) with the exception of the half-step Low A (C concert on the baritone). Basses until recent years often lacked some of the upper palm keys, but anything low Bb to high F# should be fair game nowadays. Everything above that is altissimo...beyond the normal range of the horn and created by many fingerings and air techniques to sound the higher overtones...they don't sound the same because they can't...they even lack most of the dynamic range of the rest of the horn. A high G will pop pretty good on Alto and Bari without rocking the ship...but it won't be a smooth transition in most cases. There is considerable timbral difference between an open C# and a closed D...and big changes in the palms...but like I said...I think that's the beauty of the beast. You ought to have the C# horribly out of tune on each horn too, just so no one gets their hopes up on unrealistic intonation.
By the way I was always referring to instrument keys not concert pitch. Bass in Bb, Baritone in Eb, Tenor in Bb, Alto in Eb, and Soprano in Bb...sorry if it confused anyone.
What is the range of the Saxophone 1 instruments anyway?