The PS pump should be on the left side/drivers side. That way the hoses to the box are shortest. Alternator goes to the right/passenger side.
(R/L sides of a vehicle are determined as when you are sitting in the driver's seat)
Later model brackets should bolt up.
You can use a 3-bolt ps box mount for the 4-bolt ps box... but you will be better off finding the stronger 4-bolt box.
Lots of info/discussion (and components sources) on this common swap at EarlyCJ5.net in the Intermediates forum:
Early CJ5.net > Forums
HTH, good luck!