Of course~ The only way to become an even BETTER artist is to practice things you haven't yet perfected, or use a reference to try something unfamiliar, not as comfortable, and new to expand your horizons.
At the very least, a reference is a point of comparison to help even the best of artists be sure they're achieving the look/feel they want.
that's a good thing. some artists who've been doing a lot of drawings of the same thing (human body, cars, buildings, etc.) will not always use a reference because they're very much in their comfort zone and know what they're doing by heart, making the process faster. if they are unsure about how to draw something, however, they'll have enough common sense to use a reference instead of making something up. of course they can't memorize how everything looks.
I use refrences depending on the peice. If I need it for the lighting or the way the figure is, sometimes even a facial expression. I'm currently working on a series and used my friend as a refrence model and took pictures so I knew how her hair would fall if she was upside down and what her facial expresions would be in those instances. I see no problem in using them because they help you with porportions and lighting. Even if is is just a maniquin or useing yourself in a mirror. And after a while you wont need them anymore unless your trying to show the body in a odd position for whatever reason.
References are used because the mind cannot always remember the exacts of life. Some artists use them as a guide, some use them as exacts. But all artists do use them. Think of it this way; if you are drawing something directly from your imagination, you are still effectivly referencing something you ahve seen before - be it the skin of a flying dinosar or whatever.