Alright, cracked this wide open. The shift from gen 1 to 2 airbags happened between July 19, 1997 and August 1997.

Here is specimen 1, a very late 1997 model made in 7/97 (listing). If you look up its vin (JT3HN87RXV0128670) you'll find no driver airbag since Toyota no longer sells gen 1 airbags for it.


Here is specimen 2, a very early 1998 model made in 8/98 (listing), the next month. If you look up its vin (JT3HN86R5W0132127) you'll see an airbag available (45130-35361-C0). This is a gen 2 airbag because if you look up even late 1999 models, it is the same one.

I arrived at July 19 because my 4runner is a very late 98 model, made after 7/19/98 (a part still had a sticker giving the exact date). So Toyota would change model year production very late in the month, if not at the end of the month.

It's likely that all 1998 used gen 2 airbags, not just some of them. Though IIHS says changes were made beginning with MY1998 and 1999, and the old part number for 1997 airbags supposedly fit 1998 4runners, but I have yet to see one that used it.