Space Marine setting

So I've got a setting for my gaming group that's a generic mishmash of Contra, Aliens and Starship Troopers, with a few drops of Star Wars for good measure. There's an ongoing war, and the soldiers wear low-Powered Armor (many of the soldiers have made mild customizations to the designs). Most of them have undergone certain treatments to make them 3-5 times stronger and more resilient to damage (in other words, borderline Super Soldiers).

There's another group (Project Vympel) who've undergone much more extensive genetic modifications, and have had training that make Sparta look like preschool. In addition to the normal "upgrades" the regular soldiers, they've also got a few animal-like enhanced senses, and can be triggered into a blood range via certain methods of the player's choice (such as a scent, code-phrase, or what have you).

My question is this: Should the Vympel soldiers have some sort of marking that identifies them as GEL Fs (such as a tattoo, weird eye colors, etc.) when they're unarmored? Or should they just have a logo somewhere on their uniform as an ID?

Honestly, this such a small detail that I don't even see it coming up in the story. Or if it did, you'd already have an answer to your question. For example:

Do you want someone to recognize a Vympal deserter no matter what he/she wears? (marking on skin)

Do you want someone to only recognize an old Vympal acquaintance after knocking off the Vympal's armor? (marking on skin)

Or do you want Vympals to be so proud of their heritage that they wear the symbol where all can see it? (marking on armor)

Or are you drawing these for a comic/cartoon/etc.? (either works)

Three things: Have you ever played 40k? The real 40k, not Dawn Of War. Have you read any of the Halo EU? It's got some good super-solider building stuff Why settle for a "generic" Space Marine build, with Aliens as one of the listed inspirations, when you can make your own, more flavorful soldiers, that don't drawn off of anything James Cameron ever worked on?

Maybe I'm reading too much into it. If someone has been given steroids since birth, trained unmercifully, and conditioned to kill in an eyeblink, does he really need a shoulder patch to identify him as a space marine? His impossible muscles and disdain for ordinary people should be dead giveaways.

Very true.

The only attenuating factors would be if Muscles Are Meaningless, but it's doubtful that their training would involve extensive socializing and undercover training (though you never know, against human enemies being able to blend in gives raids and spy missions with GELF backup very rewarding.)

You sir are a liar and a cad and you disgust me. Playing 40k won't give you any feel for SPESS MAHREENS as Space Marine. Do W 2 probably will, but you'd be better off reading Brothers of the Snake. At least make a useful recommendation.