Like the pic posted, a real full vinyl top what reachs the quarter opening glass area and A pillar post, pretty much like 71/72s. The Halo top is comonly also named as full vinyl top allong 73/74 because it was pretty much the only option available as Full vinyl top look and the most known, UNTILL, this M07 optioned cars were offered on 74s ( can't tell for sure if mid year offer or all 74 production ), which are a real Full vinyl top but not really common.
Dealerships databook doesn't talk about this option, however I can find these on my April 74 parts manual catalog, which obviouslly covers second half production, so it can be pretty much a mid year offer, at the same time SS came out to the market!
Once again need to say, this M07 finish was not part of the SS package but an option ( per SS advertising description ), and was NOT exclusive to SS Per what I have found allong the years surfing around.