I don't think so. After 5 years of training, your positions should be good. The only difference is that your controlling your opponent by gripping the body rather than the gi making the game slightly "looser." Positions and submission concepts are similar though - less submission options and slightly different set ups. Rather than locking the arm from the guard position using the gi and swinging your hips around for the armbar, you have to control the arm being attacked and "climb" higher keeping everything tighter to get the sub, for example. A little more work keeping everything tight.