[motan]

Hi, thanks for sharing your Majdalis with us. Indeed, the third one from the left is the oldest and most beatiful. The fourth from left is also a very good one. Both share style elements with each other and with mine and could well have been made in the same workshop. However, by the 1940's, less attention was given to the blade and more to the ornamental value. The blade of the first one is hard to evalute because it has been re-sharpened very often, but it is better than in the newer one where the fullers are not forged and are rather crudely executed like in many Lebanese and Syrian daggers of this period. Is the date written in Gregorian of Hijri calendar? If you will send me clear pictures of the inscriptions, I will ask my friend to translate them for you.
The second from left is a type produced en masse in 1950's and 60's by a certain workshop with progressively lower quality. I also own one of this type (see pictures). The scabbard is a later and ugly replacement, but the dagger has one special feature: the grip is decorated on both sides. Notice the similarity between the reverse side in mine and your dagger.
As for the forth, according to my information, this type is made in Syria for the Jordanian tourist market. There is a similar one currently on sale that has BATRA (Petra in Arabic) written on the blade. Majdali type daggers are currently made in Syria (several locations including Damascus), Southern Lebanon and even Iraq!