Floor pan & seat mounting issues ??

When I bought my car one of the front drivers seat mounts had ripped out of the floor, so I had it repaired by welding a steel plate with a welded stud onto the floor. Worked great, but today I went to install my 2000 GT seats and saw that the other front driver seat mount has come out in the same way...

Which of the foxbody seat mounts use bolts and which uses studs? It apprears my 1990 has bolts through the rear mounts and studs on the front. Is that how it should be? I guess I will just have a plate welded in to repair the other mount but I don't know why this has happened again...

I haven't had any problems with the floorpan where rearward mounts for the front seats are, though that seems to be the area most people have problems with. I should be getting SFC's with seat cross braces installed soon anyway so hopefully after that I shouldn't have any more issues... now I'm paranoid about the passenger seat though. I guess floorpan problems are just fairly common for these cars?

I found them online from a local guy who swapped them out for leather. Gotta love the power of the internet.

I seem to have some sort of reinforcing plate across the floorpan at the rear bolts... is this the same thing that comes on the SSP cars? It's definitely a factory installed piece, but I never heard of them coming on civillan models...