Berreta became the official NATO manufacturer of the M1 in Europe in the early '50s. They made a bunch for the Danes as well as for themselves before using the equipment to produce the BM-59. They also made tons of replacement parts the Danes. Funny you should ask about its value relative to a Winchester, because they were given Winchester's M1 forging and tooling equipment as part of the Truman Doctrine and the Marshall Plan. Berreta was supposed to have turned out a better product than Winchester, which has a reputation for rough finish work on its receivers and parts.
I heard that SA Inc used some Berreta recievers in their "new" Garands, as well as Berreta parts. Much better to get one with a Berreta reciever than a Lithgow (junk) receiver. As for value, depending on its condition, I don't think it would really be worth much more than a Winchester in similar condition. It certainly is not worth any more than one of SA Inc's "new" Garands. Without seeing it, I'd say $600-$800 would be a ballpark figure if its in good shape w/tight muzzle and low throat erosion. Maybe $900 if its all original parts.