Number, Murthy law firm (http://www.murthy.com/) has clearly stated that in such situation if your H1 has been approved before your OPT expires then you don't need to spend money on takin new I-20.However, other lawyers recommend you should take new I-20 as the USCIS might be interested to know what you would do during that gap period. So, it's kinda confusion state.My recommendation,if you not sure take new I-20 and feel safe.