Will the pre 2017 fit my Israelie Mark I? Would a reflex sight endure the energy imparted by that big slide slamming back and forth?
The IMI guns, (now called Mark Is) made in the 80s are absolutely "pre-2017"
From the drawing in the link, you should be able to just look at your gun and tell which version you have.
I'm sorry I can't tell you anything about the endurance of reflex sights. I don't use them, and don't have any experience with them.
What I can tell you is that it is a BAD idea to mount any scope or red dot that uses a tube like a scope ON A MOVING PART.
A few (foolish) people mounted scopes on the barrel assy of the original Auto Mag pistols, and discovered, in fairly short order that it was a scope killer.
The scope that would last forever mounted on an equally recoiling revolver or single shot nearly always died early an early death if mounted on the recoiling barrel assy of the Auto Mag. A different mounting system, where the mount was attached to the FRAME did not kill scopes.
Also, I have seen scopes, that were rated to survive elephant rifle recoil die rapid deaths when mounted on an AIR RIFLE!!!
The reason for this is simple, once realized. Scope makers generally make scopes for firearms to withstand any anticipated recoil, but only in one direction. Backwards. A shock in the other direction (forward) even if ligter than the recoil pulse is a shock in a direction most scopes are not made to withstand.
What usually kills a scope mounted on a moving slide isn't the recoil force, its the force from the sudden stop when the slide SHUTS.
Force in the forward direction is what killed some scopes on some air guns, too. The springs gave the gun a forward thrust the scope couldn't handle. I doubt any shooter would even notice.
I have a scope mount for my Desert Eagles (which are "Mark Is"), it is a weaver type rail that clamps on the BARREL. a Desert Eagle barrel is fixed, and does not move. Good solid spot where the only force on a scope or dot sight is recoil, not recoil in one direction, with a sudden stop when the slide stops moving back, and then another sudden stop in the opposite direction when the slide shuts.
So, I don't know if a reflex type sight will take that. Probably, I'm sure the makers will tell you it will. The only way to know for certain is to get one and run it and keep an eye on it for failure, noting when it does, IF it does.
Some years back I bought a cheap ($30) red dot sight (the kind with a scope tube) and put it on a .45-70 Contender. Mostly I was curious, having never used a dot sight on a pistol before, and it taught me a few things. I didn't expect it to last, due to the heavy recoil but stopped worrying about that after it passed the 200 round mark over a decade ago...
the one drawback I can see with the mount you are considering is that it replaces the rear sight. SO if your optic (whatever it is) fails in the field, and you don't have a spare optic you have to remove the mount and reinstall the rear sight to return the gun to service. With a scope or conventional red dot mounted on the barrel, if they fail, you only have to remove the optic, your iron sights are still in place (and, still sighted in).
Is this a big deal? not really, but there is a small risk, and that is the rear sight itself. Many times, when small parts like sights are removed from the gun, over time they get lost. No one intends for that to happen but often, it does.
Since they put that kind of sight on the slides of 9mms & 45s and they hold up well enough, they should be durable enough to last on the slide of a Desert Eagle, but there is no way to know for certain until you (or someone) actually tests it.
Good luck!
