The old saw goes: "Dress for the job you want, not the job you have." What does that mean now that the boss is dressing like you?

As more and more firms – from Wall Street to Akard Street – adopt "business casual" as their daily uniform, other lines of corporate protocol may be blurring as well. "I'm not making that much money compared to some of the guys around here who are wearing $1,000 suits. I can't do that," says Mark Roe, a clerk at the Dallas law firm Jenkens & Gilchrist, which recently relaxed its dress code. "Now that we're dressing more alike, he spent $60 on his clothes, I spent $60 on my clothes. It does kind of build a link between us."

But it might create a few awkward moments, too. If, for example, employees now have a harder time distinguishing the president from the mailboy, they may find themselves treating a new arrival in the smoking corral with a sock on the arm and, "Working hard, or hardly working? Heh, heh" – only to find they've just given Mr. Big a bruise on the biceps.

Business attire, for all its tight collars and double-breasted discomfort, at least allowed one to avoid such a faux pas. "Don't think casual dress assumes casual moments," says Doug Sokolosky, who as a partner in Dallas' Valerie & Company advises corporate clients on such issues. "If you don't know the hierarchy ... you have a tendency to relax, and that creates the opportunity for a Hallmark moment that's not necessarily what you're looking for," he says. "You always want to know who you're talking to, you always want to recognize people's position in the company."

Mr. Sokolosky's wife, Valerie, the company's namesake and founder, has written a self- published guide to address such issues, Business Casual ... Clarify Please! (available for about $8 on the company's Web site, http://www.valerieandcompany.com).

Her answer: another fashion hierarchy, this one based on casual clothes. According to the guide, there's "high-level" casual (sport coats for men, jackets for women); "mid-level" (corduroys and knit dresses); and "base-level" (jeans and more jeans). And for everyone: No mustard stains down the shirt front, or sweat pants and flip-flops. "What companies are saying to me is, 'I still want people to be crisp, clean or professional-looking, whether in jeans, khakis or slacks,'" Ms. Sokolosky says. And other hallmarks of corner-office potential remain. Even before Jenkens & Gilchrist's lawyers started dressing down, Mr. Roe says, dress wasn't a predictor of success. "It's how you act, how you respond, how you fulfill requests," says Mr. Roe, who's wearing a short-sleeved shirt and khaki pants this day. "It's job results. That's what's bringing distinction." And as for his mistaking a senior partner for Skippy the Xerox repairman ..."I still recognize the chiefs as chiefs," Mr. Roe says. "They're the guys yelling at me, 'Go do this, go do that!'"