the specs are piston material from pinging/detonating.
the color is rich
the timing may be too much cause there is no color change on the ground strap, which to me says that you have a lot of timing, or 'though very unlikely' not enough.
the ceramic could be almost white up top, it's the lower portion that needs a lil color wether it tan or grey'ish 'todays gas color'
the idle could be too fat as well being that there is soot build up on the base ring, you want the base ring to be black'ish, but not sooty....u also want to see some metal discoloration 2 threads down from the base ring as well., that shows about the right heat range....cause remember, just cause a low compression engine might be detonating...doesnt mean the plug is necessarily too hot, it could just be the heat generated by too much timing...and then the ping that can follow.
I say buy new plugs, or a t least one...so that u can get a better read...those look really old, and who knows whats been changed in the tune since they were installed....plugs cant clean themselves as well or at all when they've been fouled enough.
