That's the nice thing about standardisation - you can police up ammunition from bodies. Hell, that's usually the first thing I grab because it takes a damn' clip to burn through body armour.
As for radar... well boss:
Depends on the radar and the target.
I'm figuring that our radar sets are fairly good, but unexceptional - the technology of Rifts isn't the technology of the real world, but rather the future as seen from the eighties and nineties. That makes it easier to handle the 'but I want!' from folks with too much time on their hands and access to back-issues of soldier of fortune. ^_^
On that basis, most low-level ground units are going to be undetected because they're moving behind terrain features or against background clutter. Many of the large bots on the other hand will have a radar signature that sticks out like a sore thumb because they're solid high-density metal, shaped like novelty sex toys and better than thirty feet tall.
If on the other hand we were going for more modern tech... well:
http://en.wikipedia.org/wiki/B...d_Surveillance_Radar
You'd have one hell of a headache.
Oh, and thinking about it maybe the fact that so many units have a moderately good radar is why there's little or no ballistic artillery, because it's so very vulnerable to pinpoint counterfire since it can be localised within seconds?
Not that I think K.S. thought of that since if he had he'd have written a lecture on having done so and inserted it into the book in place of something less important, like the skill rules. ^_^