Close in terms of track spacing, what tape edits were made. May be more music on the master or different mixes? Maybe basic tonality. Also there may be different first pressing from various plants that sound different especially within the USA. They won't be trying to emulate bass and treble roll off and added compression. Furthermore a different mastering chain (likely superior) will not emulate the original exactly. So they are aiming at an improved version which cannot sound exactly the same. Check out information on SH/KG Rumours were there were different original versions. Some extra bits on the remaster and not sounding the same but much better.