I am at LBIA and see the whole fleet pass through. I can assure you that the 2 757s on lease from allegiant are actually left in true allegiant with obviously ammended titles.
Have a look at Jet2 holiday livery on any other plane other than LSAL, LSAM. The sceme is very slightly different with the sun being orangey instead of yellow. There was no reason to ammend the colour scheme of the 2 leased 757s as they were always going to go back to allegiant.
Hope that helps.