Can anybody ID this suspension?

I have a 91 Peterbilt 378 SBFA(set back front axle) with a 4 bag air ride steer axle. Blew a bag and nobody can find it. It's a Firestone bag but there is not enough of the part # left visible to work with. The partial part # is "6257C" We tried googling it and came up with a cross reference to a cab air bag. When compared side by side this bag is way bigger than a cab air bag but much smaller than a drive axle bag.

We hit the Peterbilt dealer and they have no listing for my truck whether or not it had air ride from the factory but they seem to think this setup is aftermarket. Last 8 of my VIN is MN308679 BTW.

Hit a dozen more truck parts places and somebody said maybe it's a KW part? Everybody is in agreement that this is an oddball part and hard to find.

I've uploaded a few photos. Any advice is welcome.

 

We were looking at the bunk airbags and these bags side by side, these are much larger.

These are about 6-8" in diameter. I'll get some exact measurements in the morning.