Well according to GIAC it has to be still on the ECU.
All socket to flash upgrades must be done via mail order at GIAC. To be eligible for an upgrade to flash, the ECU must be sent to GIAC directly with the original socket still installed in the ECU. GIAC will perform this upgrade at the cost of $75-$125 ( ECU dependent ) labor plus return shipping. To submit a request for upgrade please click the following link and fill out the ECU Service Form.
Upgrade service may be refused if the original sale can not be tracked or proven via receipt of purchase from an authorized GIAC dealer. GIAC reserves the right to modify this upgrade policy at any time. GIAC reserves the right to refuse upgrade service to anyone.
So it seems like unless you have the original ECU your stuck paying for a new tune. BTW, what happened to the old ECU?