This set of irons was custom made by MacGregor and is stamped "Jimmy Demaret, Tourney, 1630, etc."  MacGregor did not offer a 1630 iron set in their retail catalogs, nor did they offer Jimmy Demart irons stamped with their "Tourney" pro-line identifier. So we have two main possibiities here, at least as the auctioneer seed it, regarding the ownership of these clubs.  They were either made for Jimmy Demaret or for somebody who wanted to own a set of irons like the ones Jimmy Demaret used.  Given everything about these clubs, the auctioneer believes this set once belonged to the man whose name they bear.

A telling piece of evidence this set provides is that the 9-iron.  Its ferrule does not match the other ferrules, and the "1630" stamped on the 9-iron is not preceeded by "Rec. No." like it is on the other 8 irons. But the jimmy Demaret stamp on the back of the blade, the Tourney stamp, and the head itself is nearly identical.   Furthermore,  the 9-iron shows significantly more face wear than there is on the other irons.  The grips, however, match up perfectly in material, length, and "beading" underneath (more later one about this).  It's clear that the 9-iron was added to this set, and judging from the longer ferrule and slightly different grind given the back of the blade, the 9-iron came from a set made earlier than this set.  Who else would have had a second, slightly different set of 1630 irons from which to blend a used 9-iron into this set than Demaret?  He would be the most logical and likely candidate in my view.  

38 3/4" 2-Iron. Each grip is custom made with an inlayed "bead" that runs straight down the backside of each grip, underneath the leather. Consequently, these grips are not symmetrically round, but boy do they fit your hands (auctioneer would love to have everyone of his grips made this way, but, alas, they would be illegal). This is another clear piece of evidence that these clubs were custom made at a lot of extra trouble. The fact that the blended 9-iron and the other 8 irons have the matching raised bead line under their grips speaks to a singular owner who had two sets—an older and a newer set—specially made.

The auctioneer cannot prove anything, but it does appear that these 1630 irons were well-connected to Jimmy Demaret. To the auctioneer, this is the simplest and most logical answer especially given that the irons are custom top to bottom to begin with and they bear the name of Jimmy Demaret.

Jimmy Demaret was a three-time Masters champ elected to the World Golf Hall Of Fame in 1983.