Pretty much. Several years ago, someone brought in a box of sopping wet kids' art. I thought it would be pretty easy to dry out, but no. Didn't want to take the wet media off the paper, so tried drying in a cold vacuum press, with release board. The board warped in short order. Then, I couldn't figure out how to dry them without creating mold, and taking off the media by prolonged contact. A conservator once told me how they flatten rolled antique panorama photos, and it involved a special hygroscopic layer. Of something.
I just read an article that suggests freezing waterlogged books right away, to keep them in statis until repair. We usually send the rare inquiry to a conservator, but that's quite a trek.
I've only had one waterlogged frame. A lady had a burst pipe. There was mold of all colors
on the frame and back. Yellow/Purple/Red/Black/White/Green. Fortunately the artwork in the
frame was unaffected. I was very pleased about that as I framed it in the first place.