Odd (to me) rust issue - are parts available? 240/245

I bought this car (91 240 base wagon) and have been driving it because the "usual" rust spots were actually okay... rockers, behind bumpers, around glass, spare tire wells, etc. But there was some crafty undercoating done at some point, I guess, or it just degraded and hid everything...and now I've poked around and found this:

<img src="https://imgur.com/a/Gbn6XDT">
https://imgur.com/a/Gbn6XDT

It's on both sides and there's another spot like this up above the gas tank on that cross-brace. Otherwise, the car isn't too bad.

Does anyone make reproduction unibody frame rails for these things, or am I looking at custom patches? If custom, is it simply stacked 18 gauge or is it some heavier section of sheet metal, because it looks pretty thick...maybe 3/8" before it became a rust cake and over 1/4" after.

And yes, it's right above the coil spring seat on both sides

Don't think they sell that part. My friend had a car in the shop with similar rust. They welded in some very thick steel plate on all sides to beef it up. This was on an 88 wagon that other wise was in very good condition. Get you welder ready.

Better bust out the flap discs and the welder... that is odd though.

Just for the heck of it I looked in the catalog and on the gcp site; they actually still sell the RH side, but not the LH side. $321

http://www.gcp.se/en/?s=1255050.

At least I think that's the right part. #28, page 795 in the 240 1988-1993 catalog.

Oh yeah, LH side is #1255049.