Mr OCD 1 Bolt. 0 Mine are going a bit dog warred too, got to change them before too late and got to the same.
Annoying thing is I only removed the seat a few weeks ago and definitely did not do them up tight so they seemed to have tightened over time ... Very odd. I'd like to find proper sized replacements ... In titanium
I hope the longer bolts are stainless...if not the bit that's sticking out the other side will corrode and you'll never back it out! A good technique if something won't budge trying to undo it is to actually try and tighten it. If you can get it to move tighter it'll definitely come out. If you mash the head in the clockwise direction you still have your chance at the counter clockwise. If I can't get a bolt to shift I normally soak it in WD and warm it with the missus' hair drier, works every time. and not as brutal as a heat gun.
Of course they are stainless... There was no way it was coming out ... even when I drilled it out getting the remainder of the bolt out wasn't easy.
Some M6 x 10mm bolts would do the trick. Trouble is you'll need some spacers or washers to stop the bolt head going through the mounting hole in the subframe.
