I purchased a bunch of Garand ammo from a retired WWII vets son this weekend and in the bottom of one of the boxes were a bunch of full M1 carbine magazines like this. I looked at Rawles page from a previous post but he does not have pictures. Are these hardback or split magazines? I assume later because the rubber caps and is the SEY repro? They are in good condition but have a little grease that can be cleaned off. Thanks