I was in the same situation as you are today before I ted my I-140 two months ago.My second 3 years H1B was renewed on time but my I-94 was expired. When I realized this I filed I-102 immediately for replacement of my expired I-94. In the meantime my lawyer filed my I-140 with copies of I-102 receipt and H1B extension approval notice. And my lawyer told me I should be fine. Now I have got my new I-94 card attached with my I-102 approval notice and my I-140 was also approved.
So I dont think you should worry about your I-94 at all as long as you have your H1B renew approval notice on hand. File you I-102 now, good luck!