No, the sale of your property in CA would not qualify for a tax credit from OK - that credit only applies to "earned income" (i.e. from the performance of personal services).
You should, however, treat the sale of the CA property as occurring while you were a resident of CA - you placed the home on the market while living in CA, it was located in CA , it closed very close to the time you relocated to OK and any gain you had on the sale was attributable to your time in CA (not the month or so it took to sell after you left). In tax terms, there wasn't any OK nexus (connection) to the sale of this house, so it shouldn't be treated as OK income.
There is no fine-line test that determines the date you become a resident of a new state or country, as long as you are reasonable in its selection.
The date you choose as the first day of residency can coincide with one of the following events:
- You or your spouse arrived in the state or country
- Your belongings arrived
- You or your spouse started work
- You started renting your new place
- You purchased your new home
- You or a family member enrolled in school
- You or your spouse registered to vote
- You or your spouse applied for a state driver's license
