Terni Arsenal assembled the Tipo 2 rifles for the Italian Army using Breda, Beretta and Springfield receivers on hand. They did not use surplus Danish receivers for these conversions. Check the photos of Tipo 2 receivers in post # 56 and note that the flat on the receiver heel is stamped "7.62-2" to designate the use of 7.62 ammo rather than the previously standard .30 caliber (.30-06) ammo. The surplus Danish receivers which were used to assemble the Marstar 7.62 rifles do not have this stamping. And of course they also retain the Danish Crown and FKF markings to indicate Danish ownership.The shortened op rods for the 7.62 conversions were also stamped "7.62mm/2" on the handle part of the op rod.
For additional info I recommend the extremely comprehensive and well researched 872 page book, "The M1 Garand Rifle", by Bruce Canfield, an acknowledged expert on the M1 Garand and other US military small arms. Canfield's book discusses both the Danish and Italian use of the Garand and has considerable detail on the Italian 7.62 conversions, of which there are several variants;
[earlier variant discussion removed to conserve space]
-The Tipo 2, which was the standardized 7.62 model, uses all standard Garand parts, except for the shorter 7.62 barrel, stock, op rod, rear handguard and op rod spring
-There was also a Tipo 2 sniper variant which was a Tipo 2 rifle with an adapter block for the M84 scope mount
Canfield's book also has a photo of a Springfield Armory Tipo 2 receiver with modified markings on the receiver heel, including the "7.62-2" stamp on the flat of the heel, something which is absent from the Marstar rifles.
It appears that the Terni 7.62 Tipo 2 conversions were done in the mid/late 1960s based on the use of 1963 dated Springfield Armory barrels and the purpose made 1967/68 dated SIAU barrels which were used on them.