I assume you’re speaking of the CIB. That badge is not given out for just being in theatre. I wish all branches had the equivalent of the CIB. Many awards are generic and handed out like participation trophies. Not that one.
no.. in the army, the left shoulder is where you wear the patch of the unit you are assigned to...
walking around on Ft. Campbell for example.. there are guys assigned to the 101st Airborne, 5th Special Forces Group, the 160th SOAR (Nightstalkers), and a host of conventional "support" units..
you can immediately tell if someone is in an "elite" unit vs a more conventional and/or support unit just by looking at their left shoulder..
the left shoulder is also where "tabs" are worn.. tabs are given out to people that graduate from many of the armys more difficult schools like Ranger, Special Forces, Sapper, etc.. and the Presidents 100 also are awarded a "tab" (top 100 shooters in the army)...
the right shoulder tells you if someone has been deployed to a combat zone and who they were deployed with... you wear the unit patch of whatever unit you were deployed with there..
So.. for example, if I see a guy with a 101st patch on his left sleeve (with no special tabs), and an SF patch on his right sleeve, I know he deployed with a special forces unit to a combat zone, but was almost certainly in a support role rather than a direct combat role.. and now he is likely doing that same support job for the 101st.. you do get sized up however based on who you deployed to combat with.. its generally known and understood that SOF units got into the fight a whole lot more than conventional units.. and among conventional units light infantry divisions got into the fight a whole lot more than mech units (at least after the first year.. during the first year in Iraq the mech units did A LOT of fighting.. and several units did an exceptional job and covered themselves in glory).. and that active duty units generally saw more action than guard or reserve units, etc..etc..
there are absolutely exceptions to all of the above.. but generally speaking its true.. and people make assumptions..
the left chest is where you see a "CIB".. you also see airborne wings, air assault wings, scuba bubbles, halo wings, medics badges, and a host of other badges.. people definitely make assumptions based on how much fruit salad a soldier is wearing on his left chest.. for example a guy wearing an SF patch and SF tab on his left shoulder.. that also has an SF patch on his right shoulder (career special forces guy that has seen combat with an SF unit) is initially going to be sized up differently than another guy wearing an SF patch on both shoulders, but that also has a set of HALO wings and a Scuba bubble on his left chest.. generally speaking you dont get a shot at HALO or Scuba unless a) youre a stud, and b) have been around the block more than a few times...
Funny thing about the CIB.. its viewed differently today than it was in my day (or so Ive been told at least)... when I served there were only a handful of people running around with a CIB.. there were some vietnam vets still serving.. and grenada, panama, haiti, somalia, and the first gulf war were all limited conflicts that only lasted a short period of time where only a small number of soldiers were deployed (comparitively to the army as a whole).. so the CIB was extremely highly valued... and again, you made some pretty strong assumptions about anyone wearing one..
Today, we're just a few years past a war that lasted 20+ years.. almost everyone other than those that just enlisted within the last 4-5 years has had at least one deployment to a combat zone.. so almost everyone wears a CIB or a CAB or a CMB (the army now awards a Combat Action Badge to non infantry soldiers that have seen combat.. and there has been a Combat Medics Badge for a long time that is awarded to medics that have seen combat).. what guys are valuing more these days are EIB's (Expert Infantry Badges)... simply because the standard to earn an EIB is high, and because of the high deployment rate and fast optempo of the last 25 years, not nearly as many people have had an opportunity to earn them..
In my day it was pretty much assumed if you were an SF guy or an infantry guy and had been around at least 3-4 years, you were going to have an EIB.. no one really cared about them.. it was just something you did.. the CIB was what was important..
but today, everyone has a CIB... and not nearly as many people have EIB's.. so.. the EIB is now highly valued..