radio connections

[kglowacky]

just bought a oem radio for my 78. Is there a bracket or some sort of support for the back of the radio? or does the two front stems hold it in by itself?

Have 10 wires coming off two pigtail and one red hard wired wire, I know the gray and black wire (one pigtail) are for the radio light. I assume the hard wired red wire is power, are the other 8 for speakers? Two for each speaker. Can someone confirm this Thanks