No. A company announcement does not complete vetting or the applicable immigration process. Government conditions and actual instructions remain controlling.
Plan from real case events
Do not promise work or residence permission merely because sponsorship has been announced. The gift follows successful vetting and official instructions, and no fixed outcome or timetable is guaranteed.
The parts of the process that cost nothing but time, meaning the admissibility review, the family eligibility check, the cross-border tax opinion and a careful reading of the official program page, can begin before the business sale closes. Compare the pending petition's category, priority date and country of chargeability with the current visa bulletin, then compare its procedural posture with the official Gold Card sequence of fee payment, vetting, gift request, EB-1 or EB-2 approval and visa availability. Because published terms of a developing program may change, re-verify them at each decision point from the official program information, and involve a licensed U.S. immigration attorney alongside the commercial advisers rather than after them. Order the slowest civil documents first, since they depend on nobody's decision; leave the medical to the timing the instructions specify, because validity periods can lapse; hold irreversible household decisions until a visa is actually issued.