The BTS-2.0 genesis block contains two entries for the owner address BTSNwLj55sEJoAei5SHiw2APoqHh6WhHUULD:
{"amount":2304772942,"asset_symbol":"BTS","owner":"BTSNwLj55sEJoAei5SHiw2APoqHh6WhHUULD"}
{"amount":233063721,"asset_symbol":"BTS","begin_balance":437978801,"begin_timestamp":"2014-11-06T00:00:00","owner":"BTSNwLj55sEJoAei5SHiw2APoqHh6WhHUULD","vesting_duration_seconds":63072000}
The first one is a regular balance, the second is a vesting balance. You should have been able to import both using the private key for BTSNwLj55sEJoAei5SHiw2APoqHh6WhHUULD.
Update:
However, checking the balance_objects shows that the first one appears to have been claimed:
locked >>> get_object 1.15.96461
get_object 1.15.96461
[
null
]
locked >>> get_object 1.15.96462
get_object 1.15.96462
[{
"id": "1.15.96462",
"owner": "BTSNwMchb3hrCpcocTnHoBWouoLQ8wzRH9Zf",
"balance": {
"amount": 6286045,
"asset_id": "1.3.0"
},
"last_claim_date": "1970-01-01T00:00:00"
}
]
(BTSNwMchb3hrCpcocTnHoBWouoLQ8wzRH9Zf is the genesis balance immediately after BTSNwLj55sEJoAei5SHiw2APoqHh6WhHUULD, which shows that 1.15.96461 would have been yours.)
Similarly, for the vesting balances:
locked >>> get_object 1.15.161334
get_object 1.15.161334
[
null
]
locked >>> get_object 1.15.161335
get_object 1.15.161335
[{
"id": "1.15.161335",
"owner": "BTSNwMchb3hrCpcocTnHoBWouoLQ8wzRH9Zf",
"balance": {
"amount": 7149545,
"asset_id": "1.3.0"
},
"vesting_policy": {
"begin_timestamp": "2014-11-06T00:00:00",
"vesting_cliff_seconds": 0,
"vesting_duration_seconds": 63072000,
"begin_balance": 13435590
},
"last_claim_date": "1970-01-01T00:00:00"
}
]
I suppose you have claimed the remaining 790 BTS today, which is a pity, because it would have simplified to pinpoint when the last withdraw was made.