Yes, very suspect. One might find little wonder to the manner in which they have clearly been fastidious in doing their homework on the case after the judgement has been entered. If they had been so thorough firstly with the administration of pay, and secondly with their legalities at the time of the court case then they wouldn't have to resort to writing 'naughty, naughty' letters after the fact, and when they are still clearly in the wrong!
Incidentally, it is my understanding that a implicit contract does exist, regardless of the lack of signatures, due to the fact that you continue to show up for work every day in good faith, and they continue to pay you at the end of the month (including flying pay), thus establishing a previous course of conduct.