No name cast into it on the outer face between the spokes? Then I am going to take a guess you may have a real AMG Penta, one of the early versions. Ronal has their name cast into their wheels thats clearly visible. Guess its a copyright issue as they were AMG Penta knockoffs. I can not specificly id it to a year or model however. I don't have a chart with wheel id's for the AMG's.

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Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche