No.  Merging two item codes changes the the one item in all places in history; to match the item you are merging into. 

If I create a new item code and merge that into the old item code, would it keep the old item code's history? As apposed to merging the old to the new. 

Renumber / merge basically updates all historical references of the "before" ItemCode and changes them to the "after" ItemCode value.

Renumber maintains the history independently, under the new ItemCode.

Merge combines the history (of two or more items), under the new ItemCode.

The main difference between Renumber and Merge is whether the "after" ItemCode exists prior to running the Delete and Change utility (or renumbering multiple items into the same "after" item).

If you want ItemABC to have it's history retained under the ItemCode "ItemABC" then you can't use renumber / merge at all... because that is a primary function of the utility, to update history.