Yes there is reason to know this is not correct. Omnibus bills are a gimmick by the party in power, currently the Republicans. Trump could have vetoed this bill and forced Congress to send him a separate appropriations bill for the defense department which is the normal way of appropriating: 12 spending bills for each major department of government. That’s as close to a line item veto as we can get.
Looks like the Senate had the votes to override a veto.
The House, a bit shy