Yes. I got positive OPKs all the time after stopping birth control. I NEVER ovulated and had a 120+ day cycle and ended up needing provera and clomid. So it is very possible. The only way to really confirm ovulation FOR SURE is a blood test, to get a bfp, or get af.
I liked to pay attention to my signs after ovulation and when my nipples started hurting, I knew for sure ovulation had occurred.
I hope I answered your question. Good luck!