I Am A Homehealth Nurse, Finding 1/2 Pill In Client

I am a homehealth nurse, finding 1/2 pill in client medi-set, It has a V on onside and I could see 66 on opposite side, He has pain management contract, I know Hydrocodone 5/325 ends in M..65 and 10/325 or 500 has last two numbers are M..67, So I am wondering if the ..66 means this could be 7.5mg hydrocodone. I've only rarely seen any Docs here subscribe that strength. Any Idea?