Radiate Crowns On Lrb's... Any Meaning Or Significance?

Starting with Nero in 66, the radiate crown was used to indicate a double denomination when worn by the emperor on a coin. Thus, a worn dupondius could be differentiated from a worn as.

This was carried over to the antoninianus in 215, and stuck around long after the dupondius was rendered obsolete by inflation. The Antoninianus came to a formal end under Diocletian, when the reformed currencies were introduced. Then under Constantine and his boys, the radiate crown makes a brief, scarce to rare reappearance. See:

http://www.tesorillo.com/aes/_anv/c...ntinus_i.htm
http://www.tesorillo.com/aes/_anv/c...tinus2_i.htm
http://www.tesorillo.com/aes/_anv/crispus_i.htm

I have never actually come across one of these in person (except for a worn and harshly over-cleaned example that *may* be Licinius I), so I take them to be uncommon issues, along with the helmeted busts and the ones with those cute miniature horses. Are these just ornamental, meaningless radiate crowns to invoke association to Sol, or could they still retain the "double value" meaning in this case?