Can a ob/gyn diagnosis you with PID without doing cultures?

Pid. Yes. It is a good practice to do cultures. But by the time symptoms of pid appear, the original bacteria is often no longer there. What we find instead is a mixture of other opportunistic bacteria that does not help the treatment.
Probably. Pid is a pelvic bacterial infection usually due to chlamydia and gonorrhea. We suspect pid if a patient may have been in contact with an std and has a fever with significant tenderness on her pelvic exam. A diagnosis of pid may not always be accurate: other problems can cause the same symptoms. If pid is suspected, though, cultures should be done, but treatment should start asap.