How about "EIRB" for "exclusively identifiable rebar"....?;-)
I agree that you should describe what you see. Not shorten a lot of things to a couple of code letters, and also not extrapolate things you can't see. That is, if I measured the diameter of a rebar, I would express that measurement and not assume it to be a "#5" unless was able to see the number on the side of the bar. If I had a "faded yellow plastic cap that was only partially legible I would write down only the numbers or letters that I could read....etc. Guessing the type of stone, or whether a capped metal bar is actually a pipe (whether it's hollow or not), or a size you can't measure, might be a bad idea.
(Not against shortened codes for the data collector, but be able to put down more complete descriptions either on paper or in the machine). Also carry paper and a pencil and take a rubbing if it is a substantial cap if necessary.