Sorry, but this is yet another sh$thouse rumour with no basis in fact.
The Greek military received a large endowment of M1903 Springfields, M1 Garands and other US military small arms from the US in the 1940s and 1950s under the provisions of the Military Aid Program (MAP). This equipment was first intended to gear up the Greeks to supress the Greek communist elements in the Greek Civil War in the late 1940s and then to bolster Greek military capabilities as a member of NATO. The US had replaced the Brits as the primary military sponsor of the Greeks in the late 1940s after the Brits initially sent troops and equipment to Greece from Italy in 1944/1945 to stand off the Greek communist elements in the vacuum which was created by the Nazi withdrawal. The Greek military continued to use a hodge-podge of Brit and US weapons and equipment, most of which was provided gratis. Ownership of US equipment provided under the MAP programme was retained by the US who have the right of ultimate disposal. The Greeks never purchased or owned this equipment, so had no right to dispose of it by sale. Over the years there has been a trickle of Greek surplus weapons, ammo and related spares sold off, including some fine Long Branch No4s, excellent Greek made HXP .303 and .30-06 ammo, and quite a lot of spare parts and accessories for M1 Garands, No4 LEs and M1903 Springfields. A lot of this stuff is currently being sold by Greek surplus dealers on Ebay.
The US Army has repatriated a large quantity of MAP supplied surplus M1903 Springfields and M1 Garands from Greece over the past 10-12 yrs for subsequent sale through the US Govt sponsored Civilian Marksmanship Program(CMP) to qualified US citizens. Other than sales of related ammo and repair parts thru Greek surplus outlets, all US supplied Garands and M1903s have been disposed of in this manner. All of these Garands and M1903s were supplied to the Greeks on loan thru the MAP program, so Greece never had ownership of them and has no right to dispose of them by sale. By US law US made military surplus firearms cannot be imported into the US for sale to individuals , except thru the CMP.
Denmark was a different case as the Danes owned a mixture of US MAP supplied Garands as well as additional Garands which they purchased from both the US and Italy (the well known Breda and Beretta made Garands). In the case of Denmark their MAP supplied Garands were disposed of via the CMP, but the Danes did sell off a large quantity of US and Italian made Garands which they has purchased, and which were therefore free for disposal/sale as they wished. The Canadian market was once glutted by these rifles starting 20 yrs ago as they were disqualified from import into the US outside of the MAP import/CMP sale route. Many of these rifles were subsequently stripped down into parts kits, less receivers, for sale in the US. The inexpensive $50 Breda and Beretta Garand receivers which we see for sale these days are the residue of this parting out exercise. They are a great starter kit for a built up rifle as long as a person has the time and $1200-$1400 required to round up all of the other parts required to build a complete rifle on them.
There is still a large qty of US supplied small arms, incl M1 Carbines and Garands, in both Korea and the Phillipines. The ultimate disposition/disposal of these rifles has not yet been decided on, but there has been no decision to release these into the international surplus market. Most speculation is that they will ultimately be demilitarized/destroyed, although there is a possibility that some might be returned to the US for sale thru CMP channels.