barrel threads on an 1858 Remington

[crossfire]

My son found an 1858 Remington in a pawn shop for $100. The barrel is 5.5". He wants to get a longer barrel from VTI and a conversion cylinder from Taylors and install them. My nephew has a shop with a vice and tools to do the barrel swap but I have a couple of questions.
Are the threads on the barrel left or right hand? Are Pietta and Uberti barrels the same?

[Junkman]

The threads are right hand, but I don't believe the barrels are the same.

[Pettifogger]

Also, don' forget you'll also need a longer loading lever.  The lever holds the base pin in.