The only thing the 1982 law did was add a 1-year-residency requirement for the parents before you could get a birth certificate for your child born out of state. There's nothing to indicate you couldn't get such certificates prior to that. The COHB program suggests you could.
Speaking of out-of-state births, on a hunch, I checked the natality report from 1961.
http://www.cdc.gov/nchs/data/vsus/vsus_1961_1.pdf
Go to page 49. It says the table only includes births within the United States. But, better yet, it talks about how many Hawaii-listed births took place in other states to Hawaiians and part-Hawaiians ... 336 total. That’s a pretty large number. Granted, Obama’s mama wasn’t technically Hawaiian or part-Hawaiian in terms of race, but she could have easily had her child out of state and reported it in Hawaii, since we now see that Hawaii kept track of how many children born out of state.