1997 Mazda Miata Front Clip Replacement and Air Bags

My Miata was sitting still and backed into by a large pickup. It needs extensive front end repair. So far everyone who has looked at it (my body shop and adjusters from both insurance companies) agrees that the hood and the front body clip (I understand the latter is all one piece) need to be replaced. The hood has yet to opened and no telling what additional damage may be found as repairs progress.

My main question comes from a conversation with a guy I know who owns a same vintage Miata that he uses almost exclusively for road rally type races. He says that the original front clip attachment method (welds to frame) is defective and should be replaced with a Mazda approved (supplied?) Bolting system. I haven't been able to locate any service bulletin to confirm this or find any related discussion on the internet. Is this guy just blowing smoke or could there be something to this? I haven't contacted Mazda yet.

I also have some concern about the air bag system. It did not deploy and probably should not have given the relatively low intensity of the impact. The estimator at my shop gave some rigamarole about there being some difference between being backed into and a normal front end collision as far as the "decelleration" sensors" are concerned. I did study physics in college and her explanation doesn't jive with my half remembered understanding of "inertial frames of reference." Is there really any difference between driving forward into a barrier and being backed into while sitting still?

As a practical matter I want to know what assurance I can get (preferrably in writing) and from who that the air bag system, after all other repairs are made, can be expected to perform as intended in the future. So far all I have heard is that if the indicator light functions correctly (it does) everything is hunky dory. I had a very unpleasant experience landing in a large commercial jet with my head between my knees and no one knowing if indeed the landing gear was locked. An indicator light was not functioning properly.

Thanks